Starter problems Yanmar 3GM30

Jul 4, 2015
436
Hunter 34 Menominee, MI; Sturgeon Bay WI
Hi;

Am experiencing frequent intermittent starting problems when the engine is warmed up. Usually out on the water it takes several (2-3) turns of the key before the starter will kick in. New cockpit instrument panel was installed two years ago with new switch, but this preceded it. Batteries new and always charged.

Is it something to do with the starter itself/ solenoid? All terminals are clean and corrosion free and tight.
Thanks. Ilan
 
May 24, 2004
7,164
CC 30 South Florida
Old wiring (10+ years) induces voltage drop to solenoid. It likely has nothing to do with the engine being warm but what is going around when the engine is warm; batteries in discharge mode, hot wiring. A good cleaning, brushes replacement and bench testing of the starter itself will be money well spent. The solutions for the voltage drop malady are the addition of an auxiliary solenoid, replacement of wiring harness and push connectors or the rewiring of an external circuit to solenoid. Some have moved the push button starter switch to near the engine compartment or added an adittional one.
 
Jul 8, 2005
519
Jeanneau 389 Grosse Pointe Farms, MI
Hi;

Am experiencing frequent intermittent starting problems when the engine is warmed up. Usually out on the water it takes several (2-3) turns of the key before the starter will kick in. New cockpit instrument panel was installed two years ago with new switch, but this preceded it. Batteries new and always charged.

Is it something to do with the starter itself/ solenoid? All terminals are clean and corrosion free and tight.
Thanks. Ilan
Ilanortho,
We have a Beneteau 321 with the same engine and had the same issue about 15 years ago. I even replaced the starter solenoid and that was not the issue. As you will find in other posts, it is a poor wiring harness with connectors that corrode. With the help of a friend who had the same boat, we ran a solid wire from the starter button to the starter solenoid. Never had the problem again since.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Hunter in its wisdom put something like 13 connections between the battery + , start switch, solenoid, starter, ground circuit, battery - and each one has a small voltage drop. Many use an additional solenoid but that is just treating the symptoms (IMHO). Better to neuter the engine harness of ALL its quick connect plugs or run a dedicated wire from starter switch to solenoid. As a quick fix try taking all the engine harness quick connect plugs apart and after inspecting for corrosion, put it back together again.
An additional advantage to neutering the engine harness is that the instruments read properly. My engine temp always read hotter than I knew it was till I fix the wiring, the tack settled down also.
 
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Mar 30, 2013
700
Allied Seawind MK II 32' Oologah Lake, Oklahoma
As others have said the 1st thing to do before replacing expensive parts is to clean all your electrical connections related to the starter circuit.
 
Apr 22, 2011
923
Hunter 27 Pecan Grove, Oriental, NC
There is a condition called "heat soak" that occurs when a starter and solenoid get hot. This creates more resistance in the starter and solenoids wiring thus requiring more amperage from the battery to do their job. This is likely why you are only having problems when the engine is hot. Sooner or later though, you will probably have starting problems when the engine is cold.
 
Feb 22, 2011
76
Hunter Legend 37 Muskegon, MI
Similar problem. Same PITA. Mine starts every time at the dock but after about 5 hours of sailing (with a cooled engine), it doesn't start. Usually when I am either in or approaching the channel to Muskegon Lake. I let my wife take it and I go below. No not to let her have the problem but to jump between the hot post of the starter and the solenoid on the starter with a screwdriver. It miraculously starts effortlessly when I do this. Next on my to do list is (as mentioned before) run a dedicated, solid wire from the starter button to the post on the solenoid. Connectors are good, until they ain't. Try this with your HOT engine and see if you get the same results I do with a cold engine.
 
Jul 4, 2015
436
Hunter 34 Menominee, MI; Sturgeon Bay WI
Thanks again. (Last time I stuck a screwdriver in there on a bouncing boat I almost spot welded it to whatever ground it found.)
 
Jun 4, 2004
287
Beneteau Oceanis 352 NYC
i had the same problems years ago, listened to all the suggestions on this site and nothing worked. I ran a 10awg wire to replace the 12awg and haven't had a problem since.
 
Feb 16, 2021
349
Hunter Legend 35.5 Bellingham
I’m noticing the same issue. I’m measuring 10v at the solenoid when cranking the engine. This should be 12 V, correct? So I am losing 2V somewhere between the start button and the solenoid?
 
Apr 25, 2024
359
Fuji 32 Bellingham
That's a big voltage drop, in particular because your battery is probably > 12V. I would be surprised if simply installing a larger wire would fix that. I would just keep testing the voltage, starting at the solenoid and working backward toward the battery until you find out where the drop is actually occurring.

I am very curious.
 
Feb 16, 2021
349
Hunter Legend 35.5 Bellingham
Where would I check next? The only other obvious place is at the starter switch. The wire runs into unknown recesses of the boat between those two points.
 
Apr 25, 2024
359
Fuji 32 Bellingham
Well, one easy thing you can do is test right at the battery. If the voltage drops under load, at the battery - there's your problem.

It doesn't take much further before I am out of my depth and would call my friend that actually knows about these things.
 

leo310

.
Dec 15, 2006
646
Catalina 310 44 Campbell River BC
Look at your wires to the starter from the battery. the switch is only for the solenoid. Had a problem turn out bad ground wire.
 
Jun 17, 2022
210
Hunter 380 Comox BC
The yanmar wiring harness is notorious for getting microbreaks and becoming brittle once it gets to 25-30 years old.... Time to remove it and pull new wires for the engine (12V power, ignition, start signal, oil px, coolant temp, etc....). Takes about a day on most boats. Suggest using marine grade tinned instead of the copper Yanmar used. The materials will cost you about half of what they sell the harnesses for (if you know how to do proper sealed marine crimps). If you're paying someone to do it, it would likely be cheaper to just buy the new harnesses (one for the engine, one extension to the controls. Just did this on a 3GM30F.