I have a Yanmar 2GMF...5 years ago, I notice some oil under the sole at
the front of the engine....pretty easy to determine where it was coming
from...you could see the leak on the lower front of engine....only
leaked a few drops when the engine was running....no leak with the
engine stopped. Cleaned the area up and you could actually see where
the gasket was split and thus the oil leak.
Bought a new gasket but even though I might consider myself a DIY guy, I
wasn't going to attempt to take the front of the engine apart....I might
get it apart but would I get it back together.
Talked to a few diesel mechanics at the club who said they would do it
but it would cost....not overly difficult for them but time consuming
....like many boat projects, part(s) are minimal cost, labor cost is high.
Friend was aboard one day...he can do this kind of work....we talked it
over...told him I had the big gasket.....he really didn't want to do it
so he told me to go to Canadian Tire and buy a $10 tube of Ultra Copper,
clean the leak area with acetone and apply the stuff with your finger
over the leak.
That was 5 years ago, there has been no oil leak since, I still have the
old tube of Ultra Copper and I still have the new gasket on board.
Some day I might get the new gasket installed, and then as long as the
Ultra Copper keeps the oil from leaking, I may not incur the
expense.....maybe the next owner will and I even give him the gasket.
Rob Abbott
AZURA
C&C 32 - #277
Halifax, N.S.
On 2018-12-06 2:48 p.m., Josh Muckley via CnC-List wrote:
I've been living with oil leaks from around the HP fuel pump and the
timing cover for as long as I've owned the boat (~6.5 years). I
finally had a window of time to make fixing the problem a priority.
Everything went smoothly and the engine is back together and works. I
came away with some observations and questions though. To start here
are some pictures/video of the cover before reinstalling.
https://drive.google.com/folderview?id=1gNX3pjZrcabZ2LUE6rKQAm_M1jVfweR7
I didn't have power tools available and some tight tolerances on the
engine block only allowed me to get the gasket seating area as clean
as you see it in the pictures. No large or thick chunks and most of
the remnants were feathered in. Anybody have experience getting a
seal with this much residue?
The old gasket was pretty clearly a paper type which had hardened.
The new gasket was a lead/babit/graphite material. Smooth and
semi-reflective. My only hesitation was weather or not to use a
sealant. And the lingering question of, "Why did the OEM change the
material?" What are the benefits of a graphite gasket? RTV sealant
or not? I ended up using just enough RTV sealant on both sides to
provide a light smooth coat.
The ignition timing is set by the shims between the HP pump and the
timing cover. There is a timing procedure which I did not perform.
Instead, I simply replaced the shims that were there with new ones of
the same thickness. Anything that messes up that thickness will
change the timing so the use of a THIN sealant is required. Remnants
of sealant and damage to the shims made measuring the thickness of
each shim tricky. I tried to measure a combined thickness of the
stack of old shims and compare it to the thickness of the stack of new
shims, because of the combined effects of damage and sealant, the old
stack measured about 50% thicker than the new. I measured and
remeasured and I am extremely confident that I selected the exact same
number and thickness of replacement shims as was installed by the
OEM. I can't recall the source but Blue Locktite is evidently the
recommend sealant. I realize that Locktite makes a number of
different products in various colors, not just thread locker. There
was an associated product number which I was also unable to recall.
Instead of loosing sleep I just used the blue threadlocker which I had
laying around. A light wet coat on both sides of each shim.
While I was in the project I found one of the studs for the HP pump
came out. The nut was seized mid-thread and it appeared that the stud
may have been bottoming out in the timing cover, not providing the
required pressure to that corner of the HP pump. Also contributing to
the oil leak.
So the moment of truth arrived and the engine started without a
hitch. I immediately noticed that it seemed to idle a little faster.
I let it run in gear at about 2k rpm for about 2 hours before having
confidence to leave the dock. No oddities except slightly higher idle
rpm. While running around on the water I tried full throttle/rpm to
see if there was "more power". Throttle felt smooth and responsive.
It seemed like a higher rpm was achievable. Typically, with a dirty
prop and bottom 2800 or 3000 rpm is the most I would get before black
smoke would develop. This time I got to about 3400 rpm with no black
smoke and more throttle. This all seemed very positive. If I pushed
the throttle just a tad further the engine would immediately lose
significant power and blow black smoke. I realize that the tachs on
these engines are notoriously inaccurate. Mine measures about 10%
low. Without getting the laser tach out I would guess that my real
instantaneous (and momentary) rpm peeked at 3750. The OEM
instantaneous rating is 3600. Thoughts? Is my experience normal for
an engine which exceeds its max RPM or is this more representative of
an engine with too much timing advance?
_
_
_Some final thoughts_.
-I think the mechanic who worked on the engine for the PO during my
purchase caused/failed to fix 3 things. First, in removing the HP pump
he broke the seal and never re-sealed it. Second, he probably
deformed/damaged the shims. Third, he failed to identify/correct the
seized nut on the stud. All of these combined to cause the primary
oil leak. They probably also contributed to a decrease in engine timing.
-In years past I had made half attempts to fix the leak. This was
punctuated by failing to successfully remove hp pump. As a result no
sealant was able to be applied and the shims where likely to have been
further damaged. I too failed to recognize/correct the seize nut on
the stud. My efforts probably exasperated the existing problems.
-As I recall, I have had to set the pitch on my max prop lower than
that recommended by the OEM (based on the engine/power and boat/Hull
combination).
-I now believe that the combined effects have "lifted" the HP pump
about 50% higher than set by the factory causing the timing to be
retarded. As a result the engine has been chronicly under
performing. Over the years I've tweeked other engine and boat
parameters around the reduced power (raised idle speed, lowered prop
pitch) and simply accepted it as normal.
-In the spring, I'll disassemble the prop to compare current settings
with OEM suggested settings. Regardless of the findings I'll probably
increase the pitch 1 step = 2° ~= 200rpm reduction.
Oh yeah, almost forgot. So far, no leaks.
Josh Muckley
S/V Sea Hawk
1989 C&C 37+
Solomons, MD
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_______________________________________________
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every one is greatly appreciated. If you want to support the list - use PayPal
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