I checked the specs of the universal glo-plugs and they average 2 ohms. This equates to ~6amps times 4 cylinders equals ~24amps. That's a pretty good amount of current draw. The way Maine Sailor makes it sound the panel is the choke point and all the current for the glo-plugs AND starter solenoid has to come from the panel and through various plug connectors and relatively small gauge wire. Each adding it's own amount of additional resistance. Not to mention poor connections, burnt contacts, and corrosion. I'm not surprised at all to see the voltage dragged down enough to prevent the starter solenoid from being able to close.
Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Aug 11, 2015 11:41 AM, "Rick Brass via CnC-List" <cnc-list@cnc-list.com> wrote: > In about 20 years of working on boats, mine and others’, the photo is the > first Universal panel I have seen with an ammeter instead of a voltmeter on > the panel. > > > > Of course the glow plugs will draw down the starting voltage. When you > power the glow plugs you are running ten amps or so across a couple > thousand ohms of resistance to create heat. If your battery is OK, and of > normal capacity, the voltage loss to the system will be negligible – maybe > 0.1v or less. But that happens any time you put a load on the system. > Doesn’t the voltage shown on your battery monitor drop from around 12.6 to > 12.4 or 12.5 when you turn on the lights in the cabin? Same thing. > > > > The only way that the glow plugs will cause a significant drop in the > starting voltage is if you have a direct short in the wiring or a defective > glow plug that is shorted to the engine block. Then you get a direct short > from battery to ground through the engine panel wiring harness, and you let > all the smoke out of the engine wiring harness. (Sorry, old electrical > engineering joke coming back to haunt me.) Which is why there is a > typically a 20 amp fuse in the power wire that supplies the engine panel. > > > > Putting a solenoid into the system so the button engages the solenoid and > the solenoid powers the glow plugs really doesn’t accomplish anything. > Unless you have the unlikely confluence of a short in the solenoid and a > short in a glow plug, in which case you get a short direct from battery to > ground and you let the smoke out of the whole boat. > > > > > > Rick Brass > > Washington, NC > > > > > > > > *From:* CnC-List [mailto:cnc-list-boun...@cnc-list.com] *On Behalf Of *Josh > Muckley via CnC-List > *Sent:* Tuesday, August 11, 2015 10:03 AM > *To:* C&C List <cnc-list@cnc-list.com> > *Cc:* Josh Muckley <muckl...@gmail.com> > *Subject:* Re: Stus-List Universal Engine panel wiring > > > > I don't have a universal or any experience with one but it sounds to me > like the glow plugs are drawing down the starting voltage. I would suggest > installing a solenoid for the glow plugs in addition to a solenoid for the > starter. The 2 articles below talk about poorly wired universal panels and > make similar suggestions. > > http://www.pbase.com/mainecruising/universal_wiring_harness_upgrade > > http://www.pbase.com/mainecruising/solder_trouble_shooting > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > > On Aug 11, 2015 8:50 AM, "Neil Gallagher via CnC-List" < > cnc-list@cnc-list.com> wrote: > > The power to the starter button is supposed to come off the switched > terminal of the glow plug button. You are supposed to to have to push the > glow plug switch and the starter switch every time you start, as the glow > plug switch also powers both the electric fuel pump until the oil pressure > builds up, and silences the low oil pressure alarm. Once the oil pressure > rises, its switch powers the fuel pump. > > I put an M30B in our club launch and it has the same setup. > > Neil Gallagher > Weatherly, 35-1 > Glen Cove, NY > > On 8/10/2015 11:15 PM, David Knecht via CnC-List wrote: > > Since I got my boat, I have been bothered by the fact that the engine will > not start in the way it is described in the manual unless plugged into > shore power. The manual says to hold the glow plug button for about 30 > seconds and then while continuing to hold that button in, push the start > button. When I do that, the starter does not turn over. If I release the > glow plug button and push the start button the engine starts fine. My > father (retired electrical engineer) and I (genetic engineer- useless in > this case but sounds good) spent some time trying to diagnose the problem > this weekend and found two interesting things: > > > > 1. The buttons both tested fine in terms of their switch function. We > then tested power at the engine. There is a heavy red cable coming from > the battery to the starter measured 12V. The red-yellow wire from the > start button is attached to what I am presuming is the solenoid (the wiring > diagram in the manual does not show a solenoid). We only measured 8 volts > at the solenoid when the button is pushed, but 12 volts everywhere else. > So that probably explains the fact that both the glow plugs and starter > won’t work at the same time because we appear to be losing 4 volts in the > solenoid. I will pull the starter next winter and have someone test it > unless someone has an alternative suggestion. > > > > 2. The wiring diagram in the manual (Fig 2 on page 13) shows the power > from the key switch coming into the glow plug button and then a wire from > the other lead to the start button. The manual shows that wire running > from the downstream side of the glow plug switch so that the start button > should only be energized when the glow plug button is pushed (as the manual > describes). If that were the case, the I would not be able to start the > engine with only the start button. Nevertheless, it does start the > engine. Tracing the wires, we found that the bridging wire actually came > from the hot side of the glow plug switch, so that either button will work > independently as both are always powered. What I don’t understand is why > you would wire it the other way (as the manual shows) since that would > remove the ability to start the engine without the glow plugs (as in an > already warm engine). I don’t know if the PO or some yard mechanic made > that change or if it is indicated wrong in the manual, so I am curious how > other Universal panels are wired. The way it is actually wired makes more > sense to me than what is in the manual unless I am missing something. > > > > Thanks- Dave > > > > Aries > > 1990 C&C 34+ > > New London, CT > > > > > > > _______________________________________________ > > > > Email address: > > CnC-List@cnc-list.com > > To change your list preferences, including unsubscribing -- go to the bottom > of page at: > > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > > > > > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > >
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