Re: Stus-List 3GMF knocking sound

[Frederick G Street via CnC-List]

One other option for a diesel tach:

https://www.tinytach.com/diesel-tinytach 


These can be had on Amazon for under $60.00.  I just built one into a new 
engine control panel I made for my LF38; I’ve never had either a tach or gauges 
on the boat, as it came with the original Yanmar Type A panel with a couple of 
idiot lights and a horn.

I’ll have pix to post this weekend after I (finally) launch…

— Fred

Fred Street -- Minneapolis
S/V Oceanis (1979 C Landfall 38) -- on the hard in Bayfield, WI   :^(

> On Jun 1, 2018, at 10:00 AM, Francois Rivard via CnC-List 
>  wrote:
> 
> Hi Kevin, 
> 
> The only way I know of is to use another tach...  That doesn't have to be 
> expensive or complicated.  I used my R/C airplanes optical tach to validate 
> mine and it worked fine.  You paint a sliver or white stripe on the shaft / 
> shine a flashlight on it / point the tach at it. 
> 
> They are about 20-30 bucks
> 
> R/C Tachometer: 
> https://www.amazon.com/Hangar-Micro-Digital-Tachometer-HAN156/dp/B0006N72U2 
> 
> 
> Automotive Optical Tachometer: 
> https://www.amazon.com/Neiko-20713A-Tachometer-Accuracy-Batteries/dp/B000I5LDVC/ref=sr_1_2_sspa?s=industrial=UTF8=1527864869=1-2-spons=optical+Tachometer=1
>  
> 
> 
> Good Luck, 
> 
> Francois Rivard
> 1990 34+ "Take Five"
> Lake Lanier, GA
> 
> 
> 
> 
> 
> 
> Good points Francois, I have meant to take a good look at the prop and 
> probably do need to send it off for reconditioning. 
> 
> I know the bottom is a little dirty and so is the prop. But even when 
> everything was freshly painted I still had this issue. It starts up very 
> easily which makes me think that I'm running it at a decent load.
> 
> Is there a way to determine the reliability and accuracy of the Tach?
> 
> 
> On Fri, Jun 1, 2018 at 9:30 AM Francois Rivard  > wrote:
> Hi Kevin, 
> 
> In addition to making sure the transmission is fully engaged (We had that 
> issue too, for me, it was solved with a simple cable adjustment), it sounds 
> like you should jump in the water and take a good look at your prop. What you 
> need to do is grab the blades and wiggle them against the folding axis. So, 
> not following the folding movement, the other axis -> back and forth. If the 
> tip moves more than 1/8 - 1/4 inch the hub and blades need a rebuild. 
> 
> The Martecs only go so long before needing a rebuild which consists of 
> reaming the pivot axis hole and installing a larger diameter pivot shaft.  It 
> sounds like a big deal but it's not: Last time I had it done Martec did it 
> for $80.00 plus shipping. 
> 
> The 3GM30F (I have one on my boat) is a small displacement engine (950 CC) 
> and by diesel standards: A High revver. It needs to cruise between 2800 and 
> 3000 rpm and should run about 3400 rpm flat out.  If it's in good shape and 
> it can't achieve that something is amiss: Too much pitch on the prop / dirty 
> and draggy bottom  / combination of both.  
> 
> When I had my prop redone Martec sold me higher pitch blades saying it would 
> "Run better"  It didn't. All I got was cavitation and vibrations.  Going back 
> to the original blades solved the issue.  Yes, the blades with more pitch 
> were pitted (Obvious sign of cavitation), they looked like they were infested 
> with little crustaceans that don't exist in a lake. 
> 
> When Yanmar says you should run the engine at those RPM they are not kidding. 
>  Prior owners of my boat ran it at low rpm too often and turned the engine 
> into a "Hard Starter" (What the local mechanics called it) as not enough load 
> and RPM caused excessive carbon deposits / fouled the injectors / messed-up 
> the whole thing.  it was literally a  5-10 minutes battle to get the engine 
> running on the first start of the weekend every time we used the boat when we 
> first got it.  
> 
> I "fixed" the issue by running it at prescribed RPM / running it wide open 
> for at least 10-15 mins every weekend / using Diesel Kleen Power service 
> injector cleaner.  It took over 20 gallons to really make a difference but 
> now the engine starts within a few seconds every time when cold and 
> immediately fires-up for the rest of the weekend. 
> 
> Good Luck, 
> 
> -Francois Rivard
> 1990 34+ "Take Five"
> Lake Lanier, GA
> ___
> 
> Thanks everyone for supporting this list with your contributions.  Each and 
> every one is greatly appreciated.  If you want to support the list - use 
> PayPal to send contribution --   https://www.paypal.me/stumurray
> 

___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If 

Re: Stus-List 3GMf Knocking Sound

[ALAN BERGEN via CnC-List]

I had a problem with a previous boat, engine dying at higher rpm's.  Turned
out that there was a filter on the fuel take-up, in the tank, that was
partially clogged.  Once I cleaned it, the problem went away.

With my present boat with a 3GMf engine, I had a problem with the
transmission not fully engaging.  I bought a new cone, but that didn't cure
the problem.  On further inspection, I noticed a little "play" (not sure
that's the right word) when putting the transmission in gear.  I fixed the
problem with a couple of shims that eliminated the play.  If anyone needs a
new cone, I have one for sale at half price.

Recently I noticed more vibration than usual at high rpm's while in gear.
Out of gear, the engine runs very smoothly.  I'm pretty sure it's the
cutlass bearing, which hasn't been changed since I bought the boat in
2001.  The vibration isn't so bad that changing the cutlass can wait.
I'll change it when the boat comes out next year.


Alan Bergen
35 Mk III Thirsty
Rose City YC
Portland, OR

Hey Everyone,



Well we were lucky enough to be able to take out our 34 this past Wednesday
for the Blue Angels show in Annapolis. On our way back our Yanmar 3GMF
would occasionally make a knocking sound. I'm hoping you guys might know
what could have caused it.



When it happened:

* We were about to enter into the mouth of the Magothy and I was taking
down the main. My wife had the helm and yelled up saying that something
didn't sound right with the engine. She throttled down and when I got back
everything sounded ok. She said that it sounded like it was going to die.
Like it was running out of fuel.

* We kept it running slowly for a bit without issue. Then I tried to speed
us up again. After about 5-10 mins it started making the noise again. To me
it sounded like a loud knocking or banging sound. I immediately reduced
power again and it immediately went away.



Conditions:

* At the time it started occurring we had about 1/8 of a tank of fuel.

* Heavy, choppy waves for a large portion of our trip due to lots of power
boats. However, at the time it occurred, seas were calm.

* At start up after we sailed for a bit the prop had trouble opening and I
had to reduce power a couple of times to get it to open.



Observations:

* I didn't see anything incorrect or worrysome during operation.

* No leaking oil, fuel, or water.

* Racor water separator doesn't show any water in the bowl. A little gunk
in the bottom but not much.

* When power was reduced, everything sounded normal and operated normal.



Thoughts/Questions:

* Could low fuel/dirty fuel/water in fuel make this happen?

* Could this be more of a vibration from the prop not opening properly? If
that's the case, could it be indicative of something in the strut or
cutlass bearing? We have in the past had A LOT of problems with the prop
not opening.

* I did notice that during operation on the way back that occasionally the
undulation of the waves caused some stress. I'm assuming just because of
stresses on the prop.



Today I filled up the tank and started it up in the slip. It started
immediately and didn't sound like anything was wrong. I brought the
throttle up and down and everything sounds absolutely fine. So I'm at a bit
of a loss as to what to check/do. I do know that I still need to change the
oil and I am planning on changing the fuel filters as well.



I did notice that I am able to see the notch in the prop shaft where it
meets the gearbox. There does not seem to be anything on the shaft that
would indicate that it shifted at all though. Is this normal?



Would love some help from some of the yanmar experts on here please.



Kevin Paxton

'82 34 #473

Japhys Spirit

Cornfield Creek, Pasadena, MD
___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
to send contribution --   https://www.paypal.me/stumurray

Re: Stus-List 3GMF knocking sound

[Kevin Paxton via CnC-List]

Good points Francois, I have meant to take a good look at the prop and
probably do need to send it off for reconditioning.

I know the bottom is a little dirty and so is the prop. But even when
everything was freshly painted I still had this issue. It starts up very
easily which makes me think that I'm running it at a decent load.

Is there a way to determine the reliability and accuracy of the Tach?

On Fri, Jun 1, 2018 at 9:30 AM Francois Rivard 
wrote:

> Hi Kevin,
>
> In addition to making sure the transmission is fully engaged (We had that
> issue too, for me, it was solved with a simple cable adjustment), it sounds
> like you should jump in the water and take a good look at your prop. What
> you need to do is grab the blades and wiggle them against the folding axis.
> So, not following the folding movement, the other axis -> back and forth.
> If the tip moves more than 1/8 - 1/4 inch the hub and blades need a
> rebuild.
>
> The Martecs only go so long before needing a rebuild which consists of
> reaming the pivot axis hole and installing a larger diameter pivot shaft.
> It sounds like a big deal but it's not: Last time I had it done Martec did
> it for $80.00 plus shipping.
>
> The 3GM30F (I have one on my boat) is a small displacement engine (950 CC)
> and by diesel standards: A High revver. It needs to cruise between 2800 and
> 3000 rpm and should run about 3400 rpm flat out.  If it's in good shape and
> it can't achieve that something is amiss: Too much pitch on the prop /
> dirty and draggy bottom  / combination of both.
>
> When I had my prop redone Martec sold me higher pitch blades saying it
> would "Run better"  It didn't. All I got was cavitation and vibrations.
> Going back to the original blades solved the issue.  Yes, the blades with
> more pitch were pitted (Obvious sign of cavitation), they looked like they
> were infested with little crustaceans that don't exist in a lake.
>
> When Yanmar says you should run the engine at those RPM they are not
> kidding.  Prior owners of my boat ran it at low rpm too often and turned
> the engine into a "Hard Starter" (What the local mechanics called it) as
> not enough load and RPM caused excessive carbon deposits / fouled the
> injectors / messed-up the whole thing.  it was literally a  5-10 minutes
> battle to get the engine running on the first start of the weekend every
> time we used the boat when we first got it.
>
> I "fixed" the issue by running it at prescribed RPM / running it wide open
> for at least 10-15 mins every weekend / using Diesel Kleen Power service
> injector cleaner.  It took over 20 gallons to really make a difference but
> now the engine starts within a few seconds every time when cold and
> immediately fires-up for the rest of the weekend.
>
> Good Luck,
>
> -Francois Rivard
> 1990 34+ "Take Five"
> Lake Lanier, GA
>
>
>
___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
to send contribution --   https://www.paypal.me/stumurray

Re: Stus-List 3GMF knocking sound

[Josh Muckley via CnC-List]

I may have used the incorrect term but the idea of backlash is the amount
of "gear slop" between the output of the engine and the output of the
transmission.  There is a dampener in the bell housing that has springs and
those springs cushion the changes in torque from the engine output.  The
flywheel is not heavy enough to appreciably smooth the output torque.  Over
time the springs in the dampener can become week or break allowing the 2
parts of the dampener to bottom out on one another.  You may only notice
that the engine bangs into gear a little harsh.

When the engine is running at a normal rpm the counter torque created by
the compression of one cylinder is offset by the ignition of an adjacent
and since there are three cylinders each is 120° from the other and a
relatively smooth operation can be achieved.  If a misfire occurs the
counter torque will have a more significant effect, momentarily slowing the
shaft until a total of 240° of rotation is achieved before the next
ignition.  In reality since these are 4 stroke engines every cylinder has
to travel up and down twice for each ignition so instead of being simply
120° away from the next ignition it is actually 240° on a normal cycle and
when you have a misfire it pushes to 480°.  This is exacerbated at lower
rpm where there is less inertia to carry the engine through the compression
stroke.

Compound a worn or broken dampener with an irregular misfire or a low RPM
and suddenly a pretty harsh condition presents.

Hope that explains it well enough.

Josh Muckley
S/V Sea Hawk
1989 C 37+
Solomons, MD



On Fri, Jun 1, 2018, 8:21 AM Kevin Paxton via CnC-List <
cnc-list@cnc-list.com> wrote:

> Thanks John. I'll definitely have to look at that next time we are out.
> Not sure if it's related but our RPM's don't get up to the manuals
> recommended range either. I'm not sure if it's the Tach isn't reading
> right, or the engine itself just won't get up there. I can only really get
> it up to maybe ~2200-2400 rpms according to tach. I want to say the manual
> says to get it up to 3k?
>
> I did get down on Wednesday to try it out in the slip with more fuel. I
> first ran it without engaging the prop at ~1800-2000 rpms (according to the
> tach) for a good 5-10 mins and didn't hear any abnormal noises. Then I
> engaged the prop and ran again at ~1800 rpms for another 10-15 mins and
> again no abnormal noises. So maybe it was just dirty/low fuel with all the
> rocking and rolling around stirring it up.
>
> I did notice at higher rpms the vibration was minimal, at lower rpms it
> does seem to vibrate quite a bit. I'm assuming that is normal.
>
> Josh, What do you mean by backlash? Just a large jump or something to
> cause more vibration?
>
> Thanks everyone,
> Kevin Paxton
> '82 34 #473
> Japhys Spirit
> Cornfield Creek, Pasadena, MD
>
> On Sun, May 27, 2018 at 12:05 PM John and Maryann Read via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
>> Have Yanmar 3GM and Kanzaki transmission.  Had similar issue of only one
>> blade opening after sailing, boat shaking and continuing problem after
>> trying varying speeds, reverse / forward etc.  Worked fine if starting from
>> dead stop.  Not excessive wear on blade pins.  In our case turned out to be
>> worn / polished cones in transmission.  Seems an earlier rebuild was not
>> done correctly, resulting in shaft not getting fully engaged.  Diagnosed by
>> watching prop shaft as crew engaged in gear at idle, then slowly increase
>> throttle.  Shaft rpm’s did not increase corresponding to engine.  Would
>> occasionally “grab” when higher engine rpm’s were applied.  Pulled
>> transmission (not that hard), sent to expert on Yanmar / Kanzaki
>> transmissions (VERY important), had the unit back in a week, reinstalled
>> all is well.  Some pointers picked up along the way.  1) In our case the
>> fitting attaching the shifting cable to the shift lever on the transmission
>> is a double spring push/pull fitting which must be adjusted so when in
>> either forward or reverse there is additional movement possible on the
>> binnacle.  We attach the fitting to the inner hole of the lever.
>> Lubricating spring is normal maintenance each year.  2)  The mounts are OK
>> provided you can get a finger between the base and top plates.  3)  Check
>> alignment
>>
>>
>>
>> Hope this helps
>>
>>
>>
>> John and Maryann
>>
>> Legacy III
>>
>> 1982 C 34
>>
>> Noank, CT
>>
>>
>>
>> *From:* CnC-List [mailto:cnc-list-boun...@cnc-list.com] *On Behalf Of *Kevin
>> Paxton via CnC-List
>>
>>
>> *Sent:* Sunday, May 27, 2018 10:46 AM
>> *To:* cnc-list@cnc-list.com
>> *Cc:* Kevin Paxton

Re: Stus-List 3GMF knocking sound

[Kevin Paxton via CnC-List]

Thanks John. I'll definitely have to look at that next time we are out. Not
sure if it's related but our RPM's don't get up to the manuals recommended
range either. I'm not sure if it's the Tach isn't reading right, or the
engine itself just won't get up there. I can only really get it up to maybe
~2200-2400 rpms according to tach. I want to say the manual says to get it
up to 3k?

I did get down on Wednesday to try it out in the slip with more fuel. I
first ran it without engaging the prop at ~1800-2000 rpms (according to the
tach) for a good 5-10 mins and didn't hear any abnormal noises. Then I
engaged the prop and ran again at ~1800 rpms for another 10-15 mins and
again no abnormal noises. So maybe it was just dirty/low fuel with all the
rocking and rolling around stirring it up.

I did notice at higher rpms the vibration was minimal, at lower rpms it
does seem to vibrate quite a bit. I'm assuming that is normal.

Josh, What do you mean by backlash? Just a large jump or something to cause
more vibration?

Thanks everyone,
Kevin Paxton
'82 34 #473
Japhys Spirit
Cornfield Creek, Pasadena, MD

On Sun, May 27, 2018 at 12:05 PM John and Maryann Read via CnC-List <
cnc-list@cnc-list.com> wrote:

> Have Yanmar 3GM and Kanzaki transmission.  Had similar issue of only one
> blade opening after sailing, boat shaking and continuing problem after
> trying varying speeds, reverse / forward etc.  Worked fine if starting from
> dead stop.  Not excessive wear on blade pins.  In our case turned out to be
> worn / polished cones in transmission.  Seems an earlier rebuild was not
> done correctly, resulting in shaft not getting fully engaged.  Diagnosed by
> watching prop shaft as crew engaged in gear at idle, then slowly increase
> throttle.  Shaft rpm’s did not increase corresponding to engine.  Would
> occasionally “grab” when higher engine rpm’s were applied.  Pulled
> transmission (not that hard), sent to expert on Yanmar / Kanzaki
> transmissions (VERY important), had the unit back in a week, reinstalled
> all is well.  Some pointers picked up along the way.  1) In our case the
> fitting attaching the shifting cable to the shift lever on the transmission
> is a double spring push/pull fitting which must be adjusted so when in
> either forward or reverse there is additional movement possible on the
> binnacle.  We attach the fitting to the inner hole of the lever.
> Lubricating spring is normal maintenance each year.  2)  The mounts are OK
> provided you can get a finger between the base and top plates.  3)  Check
> alignment
>
>
>
> Hope this helps
>
>
>
> John and Maryann
>
> Legacy III
>
> 1982 C 34
>
> Noank, CT
>
>
>
> *From:* CnC-List [mailto:cnc-list-boun...@cnc-list.com] *On Behalf Of *Kevin
> Paxton via CnC-List
>
>
> *Sent:* Sunday, May 27, 2018 10:46 AM
> *To:* cnc-list@cnc-list.com
> *Cc:* Kevin Paxton
>
> *Subject:* Re: Stus-List 3GMF knocking sound
>
>
>
> Pretty sure it's a martec, folding 2-blade. I try to power up and it
> vibrates like crazy. I power down to try and get it to reset so that I
> don't damage anything with it vibrating so bad. Then I try again. If I
> rotate the shaft manually I can hear each blade folding open but for some
> reason it is tough to open it after sailing for a bit.
>
>
>
> Coming out of the slip it opens without a problem.
>
>
>
> The sounds came this time though while already under power and the prop
> was open.
>
> On Sun, May 27, 2018, 10:27 AM Gary Nylander via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> I’m curious. What kind of prop do you have that requires you to slow down
> to get it to open. Most folding ones ask for more speed to get the blades
> to open. Non opening would produce lots of vibration, which would get lots
> of noise as the engine bounces around on (particularly) old motor mounts.
> Shake the motor.
>
>
>
> Gary
>
> Flex-o-fold geared
>
>
>
> *From:* CnC-List  *On Behalf Of *Kevin
> Paxton via CnC-List
> *Sent:* Saturday, May 26, 2018 8:05 PM
> *To:* cnc-list@cnc-list.com
> *Cc:* Kevin Paxton 
> *Subject:* Re: Stus-List 3GMF knocking sound
>
>
>
> Yea I did that today and started it up and it sounded fine. However I
> didn't put it in gear or take it out of the slip. The racor was full and I
> didn't see any water in it either.
>
>
>
> Now it does vibrate pretty good under operation. I looked at the engine
> mounts though and none seemed to be cracked or anything. What should the
> mounts look/feel like?  How much vibration while running should it have?
>
> On Sat, May 26, 2018, 6:50 PM Josh Muckley via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Kevin,
>
>
>
> Fill the fuel tank with 6 to 10 gallons of fre

Re: Stus-List 3GMF knocking sound

[John and Maryann Read via CnC-List]

Have Yanmar 3GM and Kanzaki transmission.  Had similar issue of only one blade 
opening after sailing, boat shaking and continuing problem after trying varying 
speeds, reverse / forward etc.  Worked fine if starting from dead stop.  Not 
excessive wear on blade pins.  In our case turned out to be worn / polished 
cones in transmission.  Seems an earlier rebuild was not done correctly, 
resulting in shaft not getting fully engaged.  Diagnosed by watching prop shaft 
as crew engaged in gear at idle, then slowly increase throttle.  Shaft rpm’s 
did not increase corresponding to engine.  Would occasionally “grab” when 
higher engine rpm’s were applied.  Pulled transmission (not that hard), sent to 
expert on Yanmar / Kanzaki transmissions (VERY important), had the unit back in 
a week, reinstalled all is well.  Some pointers picked up along the way.  1) In 
our case the fitting attaching the shifting cable to the shift lever on the 
transmission is a double spring push/pull fitting which must be adjusted so 
when in either forward or reverse there is additional movement possible on the 
binnacle.  We attach the fitting to the inner hole of the lever.  Lubricating 
spring is normal maintenance each year.  2)  The mounts are OK provided you can 
get a finger between the base and top plates.  3)  Check alignment

 

Hope this helps

 

John and Maryann

Legacy III

1982 C 34

Noank, CT

 

From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Kevin Paxton 
via CnC-List
Sent: Sunday, May 27, 2018 10:46 AM
To: cnc-list@cnc-list.com
Cc: Kevin Paxton
Subject: Re: Stus-List 3GMF knocking sound

 

Pretty sure it's a martec, folding 2-blade. I try to power up and it vibrates 
like crazy. I power down to try and get it to reset so that I don't damage 
anything with it vibrating so bad. Then I try again. If I rotate the shaft 
manually I can hear each blade folding open but for some reason it is tough to 
open it after sailing for a bit. 

 

Coming out of the slip it opens without a problem.

 

The sounds came this time though while already under power and the prop was 
open. 

On Sun, May 27, 2018, 10:27 AM Gary Nylander via CnC-List 
<cnc-list@cnc-list.com> wrote:

I’m curious. What kind of prop do you have that requires you to slow down to 
get it to open. Most folding ones ask for more speed to get the blades to open. 
Non opening would produce lots of vibration, which would get lots of noise as 
the engine bounces around on (particularly) old motor mounts. Shake the motor.

 

Gary

Flex-o-fold geared

 

From: CnC-List <cnc-list-boun...@cnc-list.com> On Behalf Of Kevin Paxton via 
CnC-List
Sent: Saturday, May 26, 2018 8:05 PM
To: cnc-list@cnc-list.com
Cc: Kevin Paxton <kpax...@paxdesigns.com>
Subject: Re: Stus-List 3GMF knocking sound

 

Yea I did that today and started it up and it sounded fine. However I didn't 
put it in gear or take it out of the slip. The racor was full and I didn't see 
any water in it either.

 

Now it does vibrate pretty good under operation. I looked at the engine mounts 
though and none seemed to be cracked or anything. What should the mounts 
look/feel like?  How much vibration while running should it have? 

On Sat, May 26, 2018, 6:50 PM Josh Muckley via CnC-List <cnc-list@cnc-list.com> 
wrote:

Kevin, 

 

Fill the fuel tank with 6 to 10 gallons of fresh fuel, try it out, and get back 
to us.  Check your racor filter for air.  Low fuel/air in the line/water in the 
line can all cause rough operation.  These Yanmars have a lot of backlash in 
the engine and when you get rough operations the clutch plate springs can bang. 
 If you have a loose/broken/soft engine mount it can allow the engine to bang 
around pretty good too.

 

Josh Muckley 

S/V Sea Hawk 

1989 C 37+

Solomons, MD

 

 

On Sat, May 26, 2018, 2:30 PM Kevin Paxton via CnC-List <cnc-list@cnc-list.com> 
wrote:

Hey Everyone,

 

Well we were lucky enough to be able to take out our 34 this past Wednesday for 
the Blue Angels show in Annapolis. On our way back our Yanmar 3GMF would 
occasionally make a knocking sound. I'm hoping you guys might know what could 
have caused it.

 

When it happened:

* We were about to enter into the mouth of the Magothy and I was taking down 
the main. My wife had the helm and yelled up saying that something didn't sound 
right with the engine. She throttled down and when I got back everything 
sounded ok. She said that it sounded like it was going to die. Like it was 
running out of fuel.

* We kept it running slowly for a bit without issue. Then I tried to speed us 
up again. After about 5-10 mins it started making the noise again. To me it 
sounded like a loud knocking or banging sound. I immediately reduced power 
again and it immediately went away.

 

Conditions:

* At the time it started occurring we had about 1/8 of a tank of fuel.

* Heavy, choppy waves for a large portion of our trip due to lots of power 
boats. However, at the ti

Re: Stus-List 3GMF knocking sound

[Nauset Beach via CnC-List]

Martec non-geared props have issues with both blades opening especially if they 
get worn at the pin in each blade.  Sounds like that might be the issue.  Was 
on a J/35 in the late ‘80’s that had that issue and the whole boat would shake. 
 The owner and his son had a routine they went through to coax both blades to 
open; IIRC they went to neutral, then reverse with some throttle, then 
relatively quickly went into forward.  Might guess that put some additional 
wear on the cones in the transmission, but it seemed to work.  

 

Martec will recondition the props, but that obviously means pulling the prop 
and sending it to them…  

 

Many of us who had Martec’s have changed to Flex-O-Fold geared props to 
eliminate the potential to vibrate due to a blade not opening and for much 
improved reverse.  Have my old Martec if anyone wants it: RH  16 x 14 for a 1” 
shaft…  

 

Brian

 

From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Kevin Paxton 
via CnC-List
Sent: Sunday, May 27, 2018 10:46 AM
To: cnc-list@cnc-list.com
Cc: Kevin Paxton <kpax...@paxdesigns.com>
Subject: Re: Stus-List 3GMF knocking sound

 

Pretty sure it's a martec, folding 2-blade. I try to power up and it vibrates 
like crazy. I power down to try and get it to reset so that I don't damage 
anything with it vibrating so bad. Then I try again. If I rotate the shaft 
manually I can hear each blade folding open but for some reason it is tough to 
open it after sailing for a bit. 

 

Coming out of the slip it opens without a problem.

 

The sounds came this time though while already under power and the prop was 
open. 

On Sun, May 27, 2018, 10:27 AM Gary Nylander via CnC-List 
<cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com> > wrote:

I’m curious. What kind of prop do you have that requires you to slow down to 
get it to open. Most folding ones ask for more speed to get the blades to open. 
Non opening would produce lots of vibration, which would get lots of noise as 
the engine bounces around on (particularly) old motor mounts. Shake the motor.

 

Gary

Flex-o-fold geared

___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
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Re: Stus-List 3GMF knocking sound

[Kevin Paxton via CnC-List]

Pretty sure it's a martec, folding 2-blade. I try to power up and it
vibrates like crazy. I power down to try and get it to reset so that I
don't damage anything with it vibrating so bad. Then I try again. If I
rotate the shaft manually I can hear each blade folding open but for some
reason it is tough to open it after sailing for a bit.

Coming out of the slip it opens without a problem.

The sounds came this time though while already under power and the prop was
open.

On Sun, May 27, 2018, 10:27 AM Gary Nylander via CnC-List <
cnc-list@cnc-list.com> wrote:

> I’m curious. What kind of prop do you have that requires you to slow down
> to get it to open. Most folding ones ask for more speed to get the blades
> to open. Non opening would produce lots of vibration, which would get lots
> of noise as the engine bounces around on (particularly) old motor mounts.
> Shake the motor.
>
>
>
> Gary
>
> Flex-o-fold geared
>
>
>
> *From:* CnC-List <cnc-list-boun...@cnc-list.com> *On Behalf Of *Kevin
> Paxton via CnC-List
> *Sent:* Saturday, May 26, 2018 8:05 PM
> *To:* cnc-list@cnc-list.com
> *Cc:* Kevin Paxton <kpax...@paxdesigns.com>
> *Subject:* Re: Stus-List 3GMF knocking sound
>
>
>
> Yea I did that today and started it up and it sounded fine. However I
> didn't put it in gear or take it out of the slip. The racor was full and I
> didn't see any water in it either.
>
>
>
> Now it does vibrate pretty good under operation. I looked at the engine
> mounts though and none seemed to be cracked or anything. What should the
> mounts look/feel like?  How much vibration while running should it have?
>
> On Sat, May 26, 2018, 6:50 PM Josh Muckley via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Kevin,
>
>
>
> Fill the fuel tank with 6 to 10 gallons of fresh fuel, try it out, and get
> back to us.  Check your racor filter for air.  Low fuel/air in the
> line/water in the line can all cause rough operation.  These Yanmars have a
> lot of backlash in the engine and when you get rough operations the clutch
> plate springs can bang.  If you have a loose/broken/soft engine mount it
> can allow the engine to bang around pretty good too.
>
>
>
> Josh Muckley
>
> S/V Sea Hawk
>
> 1989 C 37+
>
> Solomons, MD
>
>
>
>
>
> On Sat, May 26, 2018, 2:30 PM Kevin Paxton via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Hey Everyone,
>
>
>
> Well we were lucky enough to be able to take out our 34 this past
> Wednesday for the Blue Angels show in Annapolis. On our way back our Yanmar
> 3GMF would occasionally make a knocking sound. I'm hoping you guys might
> know what could have caused it.
>
>
>
> When it happened:
>
> * We were about to enter into the mouth of the Magothy and I was taking
> down the main. My wife had the helm and yelled up saying that something
> didn't sound right with the engine. She throttled down and when I got back
> everything sounded ok. She said that it sounded like it was going to die.
> Like it was running out of fuel.
>
> * We kept it running slowly for a bit without issue. Then I tried to speed
> us up again. After about 5-10 mins it started making the noise again. To me
> it sounded like a loud knocking or banging sound. I immediately reduced
> power again and it immediately went away.
>
>
>
> Conditions:
>
> * At the time it started occurring we had about 1/8 of a tank of fuel.
>
> * Heavy, choppy waves for a large portion of our trip due to lots of power
> boats. However, at the time it occurred, seas were calm.
>
> * At start up after we sailed for a bit the prop had trouble opening and I
> had to reduce power a couple of times to get it to open.
>
>
>
> Observations:
>
> * I didn't see anything incorrect or worrysome during operation.
>
> * No leaking oil, fuel, or water.
>
> * Racor water separator doesn't show any water in the bowl. A little gunk
> in the bottom but not much.
>
> * When power was reduced, everything sounded normal and operated normal.
>
>
>
> Thoughts/Questions:
>
> * Could low fuel/dirty fuel/water in fuel make this happen?
>
> * Could this be more of a vibration from the prop not opening properly? If
> that's the case, could it be indicative of something in the strut or
> cutlass bearing? We have in the past had A LOT of problems with the prop
> not opening.
>
> * I did notice that during operation on the way back that occasionally the
> undulation of the waves caused some stress. I'm assuming just because of
> stresses on the prop.
>
>
>
> Today I filled up the tank and started it up in the slip. It started
> immediately and didn't sound like anything was wrong.

Re: Stus-List 3GMF knocking sound

[Gary Nylander via CnC-List]

I’m curious. What kind of prop do you have that requires you to slow down to 
get it to open. Most folding ones ask for more speed to get the blades to open. 
Non opening would produce lots of vibration, which would get lots of noise as 
the engine bounces around on (particularly) old motor mounts. Shake the motor.

 

Gary

Flex-o-fold geared

 

From: CnC-List <cnc-list-boun...@cnc-list.com> On Behalf Of Kevin Paxton via 
CnC-List
Sent: Saturday, May 26, 2018 8:05 PM
To: cnc-list@cnc-list.com
Cc: Kevin Paxton <kpax...@paxdesigns.com>
Subject: Re: Stus-List 3GMF knocking sound

 

Yea I did that today and started it up and it sounded fine. However I didn't 
put it in gear or take it out of the slip. The racor was full and I didn't see 
any water in it either.

 

Now it does vibrate pretty good under operation. I looked at the engine mounts 
though and none seemed to be cracked or anything. What should the mounts 
look/feel like?  How much vibration while running should it have? 

On Sat, May 26, 2018, 6:50 PM Josh Muckley via CnC-List <cnc-list@cnc-list.com 
<mailto:cnc-list@cnc-list.com> > wrote:

Kevin, 

 

Fill the fuel tank with 6 to 10 gallons of fresh fuel, try it out, and get back 
to us.  Check your racor filter for air.  Low fuel/air in the line/water in the 
line can all cause rough operation.  These Yanmars have a lot of backlash in 
the engine and when you get rough operations the clutch plate springs can bang. 
 If you have a loose/broken/soft engine mount it can allow the engine to bang 
around pretty good too.

 

Josh Muckley 

S/V Sea Hawk 

1989 C 37+

Solomons, MD

 

 

On Sat, May 26, 2018, 2:30 PM Kevin Paxton via CnC-List <cnc-list@cnc-list.com 
<mailto:cnc-list@cnc-list.com> > wrote:

Hey Everyone,

 

Well we were lucky enough to be able to take out our 34 this past Wednesday for 
the Blue Angels show in Annapolis. On our way back our Yanmar 3GMF would 
occasionally make a knocking sound. I'm hoping you guys might know what could 
have caused it.

 

When it happened:

* We were about to enter into the mouth of the Magothy and I was taking down 
the main. My wife had the helm and yelled up saying that something didn't sound 
right with the engine. She throttled down and when I got back everything 
sounded ok. She said that it sounded like it was going to die. Like it was 
running out of fuel.

* We kept it running slowly for a bit without issue. Then I tried to speed us 
up again. After about 5-10 mins it started making the noise again. To me it 
sounded like a loud knocking or banging sound. I immediately reduced power 
again and it immediately went away.

 

Conditions:

* At the time it started occurring we had about 1/8 of a tank of fuel.

* Heavy, choppy waves for a large portion of our trip due to lots of power 
boats. However, at the time it occurred, seas were calm.

* At start up after we sailed for a bit the prop had trouble opening and I had 
to reduce power a couple of times to get it to open. 

 

Observations:

* I didn't see anything incorrect or worrysome during operation. 

* No leaking oil, fuel, or water.

* Racor water separator doesn't show any water in the bowl. A little gunk in 
the bottom but not much.

* When power was reduced, everything sounded normal and operated normal.

 

Thoughts/Questions:

* Could low fuel/dirty fuel/water in fuel make this happen?

* Could this be more of a vibration from the prop not opening properly? If 
that's the case, could it be indicative of something in the strut or cutlass 
bearing? We have in the past had A LOT of problems with the prop not opening. 

* I did notice that during operation on the way back that occasionally the 
undulation of the waves caused some stress. I'm assuming just because of 
stresses on the prop. 

 

Today I filled up the tank and started it up in the slip. It started 
immediately and didn't sound like anything was wrong. I brought the throttle up 
and down and everything sounds absolutely fine. So I'm at a bit of a loss as to 
what to check/do. I do know that I still need to change the oil and I am 
planning on changing the fuel filters as well. 

 

I did notice that I am able to see the notch in the prop shaft where it meets 
the gearbox. There does not seem to be anything on the shaft that would 
indicate that it shifted at all though. Is this normal?

 

Would love some help from some of the yanmar experts on here please.

 

Kevin Paxton

'82 34 #473

Japhys Spirit

Cornfield Creek, Pasadena, MD

___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
to send contribution --   https://www.paypal.me/stumurray

___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the lis

Re: Stus-List 3GMF knocking sound

[Kevin Paxton via CnC-List]

Yea I did that today and started it up and it sounded fine. However I
didn't put it in gear or take it out of the slip. The racor was full and I
didn't see any water in it either.

Now it does vibrate pretty good under operation. I looked at the engine
mounts though and none seemed to be cracked or anything. What should the
mounts look/feel like?  How much vibration while running should it have?

On Sat, May 26, 2018, 6:50 PM Josh Muckley via CnC-List <
cnc-list@cnc-list.com> wrote:

> Kevin,
>
> Fill the fuel tank with 6 to 10 gallons of fresh fuel, try it out, and get
> back to us.  Check your racor filter for air.  Low fuel/air in the
> line/water in the line can all cause rough operation.  These Yanmars have a
> lot of backlash in the engine and when you get rough operations the clutch
> plate springs can bang.  If you have a loose/broken/soft engine mount it
> can allow the engine to bang around pretty good too.
>
> Josh Muckley
> S/V Sea Hawk
> 1989 C 37+
> Solomons, MD
>
>
>
> On Sat, May 26, 2018, 2:30 PM Kevin Paxton via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
>> Hey Everyone,
>>
>> Well we were lucky enough to be able to take out our 34 this past
>> Wednesday for the Blue Angels show in Annapolis. On our way back our Yanmar
>> 3GMF would occasionally make a knocking sound. I'm hoping you guys might
>> know what could have caused it.
>>
>> When it happened:
>> * We were about to enter into the mouth of the Magothy and I was taking
>> down the main. My wife had the helm and yelled up saying that something
>> didn't sound right with the engine. She throttled down and when I got back
>> everything sounded ok. She said that it sounded like it was going to die.
>> Like it was running out of fuel.
>> * We kept it running slowly for a bit without issue. Then I tried to
>> speed us up again. After about 5-10 mins it started making the noise again.
>> To me it sounded like a loud knocking or banging sound. I immediately
>> reduced power again and it immediately went away.
>>
>> Conditions:
>> * At the time it started occurring we had about 1/8 of a tank of fuel.
>> * Heavy, choppy waves for a large portion of our trip due to lots of
>> power boats. However, at the time it occurred, seas were calm.
>> * At start up after we sailed for a bit the prop had trouble opening and
>> I had to reduce power a couple of times to get it to open.
>>
>> Observations:
>> * I didn't see anything incorrect or worrysome during operation.
>> * No leaking oil, fuel, or water.
>> * Racor water separator doesn't show any water in the bowl. A little gunk
>> in the bottom but not much.
>> * When power was reduced, everything sounded normal and operated normal.
>>
>> Thoughts/Questions:
>> * Could low fuel/dirty fuel/water in fuel make this happen?
>> * Could this be more of a vibration from the prop not opening properly?
>> If that's the case, could it be indicative of something in the strut or
>> cutlass bearing? We have in the past had A LOT of problems with the prop
>> not opening.
>> * I did notice that during operation on the way back that occasionally
>> the undulation of the waves caused some stress. I'm assuming just because
>> of stresses on the prop.
>>
>> Today I filled up the tank and started it up in the slip. It started
>> immediately and didn't sound like anything was wrong. I brought the
>> throttle up and down and everything sounds absolutely fine. So I'm at a bit
>> of a loss as to what to check/do. I do know that I still need to change the
>> oil and I am planning on changing the fuel filters as well.
>>
>> I did notice that I am able to see the notch in the prop shaft where it
>> meets the gearbox. There does not seem to be anything on the shaft that
>> would indicate that it shifted at all though. Is this normal?
>>
>> Would love some help from some of the yanmar experts on here please.
>>
>> Kevin Paxton
>> '82 34 #473
>> Japhys Spirit
>> Cornfield Creek, Pasadena, MD
>> ___
>>
>> Thanks everyone for supporting this list with your contributions.  Each
>> and every one is greatly appreciated.  If you want to support the list -
>> use PayPal to send contribution --   https://www.paypal.me/stumurray
>>
>> ___
>
> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
>
>
___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
to send contribution --   https://www.paypal.me/stumurray

Re: Stus-List 3GMF knocking sound

[Josh Muckley via CnC-List]

Kevin,

Fill the fuel tank with 6 to 10 gallons of fresh fuel, try it out, and get
back to us.  Check your racor filter for air.  Low fuel/air in the
line/water in the line can all cause rough operation.  These Yanmars have a
lot of backlash in the engine and when you get rough operations the clutch
plate springs can bang.  If you have a loose/broken/soft engine mount it
can allow the engine to bang around pretty good too.

Josh Muckley
S/V Sea Hawk
1989 C 37+
Solomons, MD



On Sat, May 26, 2018, 2:30 PM Kevin Paxton via CnC-List <
cnc-list@cnc-list.com> wrote:

> Hey Everyone,
>
> Well we were lucky enough to be able to take out our 34 this past
> Wednesday for the Blue Angels show in Annapolis. On our way back our Yanmar
> 3GMF would occasionally make a knocking sound. I'm hoping you guys might
> know what could have caused it.
>
> When it happened:
> * We were about to enter into the mouth of the Magothy and I was taking
> down the main. My wife had the helm and yelled up saying that something
> didn't sound right with the engine. She throttled down and when I got back
> everything sounded ok. She said that it sounded like it was going to die.
> Like it was running out of fuel.
> * We kept it running slowly for a bit without issue. Then I tried to speed
> us up again. After about 5-10 mins it started making the noise again. To me
> it sounded like a loud knocking or banging sound. I immediately reduced
> power again and it immediately went away.
>
> Conditions:
> * At the time it started occurring we had about 1/8 of a tank of fuel.
> * Heavy, choppy waves for a large portion of our trip due to lots of power
> boats. However, at the time it occurred, seas were calm.
> * At start up after we sailed for a bit the prop had trouble opening and I
> had to reduce power a couple of times to get it to open.
>
> Observations:
> * I didn't see anything incorrect or worrysome during operation.
> * No leaking oil, fuel, or water.
> * Racor water separator doesn't show any water in the bowl. A little gunk
> in the bottom but not much.
> * When power was reduced, everything sounded normal and operated normal.
>
> Thoughts/Questions:
> * Could low fuel/dirty fuel/water in fuel make this happen?
> * Could this be more of a vibration from the prop not opening properly? If
> that's the case, could it be indicative of something in the strut or
> cutlass bearing? We have in the past had A LOT of problems with the prop
> not opening.
> * I did notice that during operation on the way back that occasionally the
> undulation of the waves caused some stress. I'm assuming just because of
> stresses on the prop.
>
> Today I filled up the tank and started it up in the slip. It started
> immediately and didn't sound like anything was wrong. I brought the
> throttle up and down and everything sounds absolutely fine. So I'm at a bit
> of a loss as to what to check/do. I do know that I still need to change the
> oil and I am planning on changing the fuel filters as well.
>
> I did notice that I am able to see the notch in the prop shaft where it
> meets the gearbox. There does not seem to be anything on the shaft that
> would indicate that it shifted at all though. Is this normal?
>
> Would love some help from some of the yanmar experts on here please.
>
> Kevin Paxton
> '82 34 #473
> Japhys Spirit
> Cornfield Creek, Pasadena, MD
> ___
>
> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
>
>
___

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
to send contribution --   https://www.paypal.me/stumurray