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Hard Starting Yanmar

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John Foy

I have a Yanmar 3GM30 with 425 hours. It was on the boat when I acquired it 3.5 years ago. The engine runs very well and I have no complaints except that it is generally difficult to start when cold. I have tried moving the throttle all the way from barely open to wide open and nothing seems to help. I mentioned this to the local Yanmar dealer at a recent boat show and he said that maybe the battery was not providing sufficient power to turn over the engine fast enough. I just installed a brand new group 27 starting battery and this has not made any difference. Once the engine gets going it can easily be started again. I do not have any kind of electric fuel pump. Any ideas as to what is happening?

Jack Laird

Me too

Sounds like my problem also although its a Renault. See previous mail. No comment from the experts though.

Tom Senator

I'd like an answer from the experts also.

The same thing happens to me ! I have an 1980 vintage Yanmar 2QM15 and Once she is up and running she's great. But when she's cold, it takes a while to kick her over. I don't know the hours (no meter), but I've rebuilt the injectors, and adjusted the Valves, etc and no help. I don't have an electric pump either, maybe that will help, but I did put a hand held "bulb" in line pump in the diesel line going to the engine. I tried to pump it while the engine was turning over, but it didn't seem to help....any ideas would be appreciated. Yes..also... there seems to be adequate air flow in and I've checked the mixing exhaust elbow and it doesn't seem to be clogged or anything....I don't know

Bob England

Me too, 2

1989 2GM20F in H30G. Very hard to start when cold and *lots* of smoke. Stalls and needs to be restarted several times before it will keep running. Once warmed up, restarts easily, no smoke and plenty of power. 3600-3700 RPM in neutral, 3400 RPM and hull speed in gear. Will cruise for hours at 3000-3100 RPM without smoking or overheating. Injectors serviced, filters changed, mixing elbow not blocked. What gives?

Duane Maher

Yanmars have no Glowplugs and

can be difficult to start when cold. However it should not take so long to start that you fill up the water muffler (30 sec) because water can flow back into the engine. Had a Yanmar on a Caliber that took forever to start in the spring. It would start fairly well on warm days but still not like an engine with Glowplugs.

Jack Laird

Torreson non responsive

We don't seem to be getting much expert advise.

Bryan C.

Diesels are hard to start when its cold.

So are gasoline engines, but diesels more so. For gas engines, it takes longer for the fuel to vaporize in the cylinder, maybe that's the same reason for diesels. The hard starting is the reason why most diesels have glow plugs to warm up the cyclinder -- don't know why Yannies don't have them except they must figure they don't need them. I can't give much practical experience living in So Fla. However, for gasoline engines, a trick for starting in cold weather is to crank the engine over a few times, then count to 10 or 20 to let the fuel vaporiz in the cylinder. Generally then will crank over. Maybe it will work with the Yanmars.

Neil Russell

Solution to Hard Starting Yanmar

My Yanmar 3CGM was also extremely hard to start when cold. I went down the same road as most other owners in checking fuel systems, injectors, mixing elbow, etc. Finally I called a Yanmar distributer in Seattle, WA who turned me on to a small manufacturer in Bellingham, WA that custom builds an engine preheating device. This fellow sold Yanmars for many years and was well aware of their famed cold starting problem. I ordered his unit which came ready to install and fit perfectly. It also works perfectly every time.

Eric Lorgus

My 2GM20F is easy to start in warm weather

It's on an 87H285, & as far as I know, it's original equipment. Before cranking, I advance the throttle all the way open, then closed, then 1/4 open. Engine usually catches on 2nd or 3rd beat (I don't know what to call that, but when engine cranks, there's a definite rhythm). OAT during the summer on the Chesapeake is anywhere from 70's to 90's. Last fall, I did notice engine cranking took longer before catching. By then, average OAT was probably 50's or low 60's. Temperature definitely affects how easy it is to start a diesel. When temps get down to 30's, fuel begins to "wax", & if you're motoring in that kind of weather, you may need an additive. If you're having a hard time starting a cold engine in warm weather (but not if engine is warm), my guess is you have a fuel problem. Some water in the fuel, maybe? Yanmars will tolerate some water but not a lot. Many diesels just won't light if there's water in the fuel. Ruling out fuel problems includes replacing both filters, and possibly getting your fuel tank cleaned. Don't forget to check the o-ring on your fuel filler. If it's worn or missing, your definitely getting water in the tank every time it rains.

Christopher VanOosterhout - Torresen

Ideas about Yanmar starting problem

Greetings, Here are some of the things that we may suggest in your situation this response adapted from another posting by Gordon Torresen about a similar problem from another user) There are a number of things that must be right to start and engine, especially on the first try of the day. I will enumerate those that come to ind. 1 - Injection timing - very critical and the most difficult to correct. This should be the last thing to evaluate and correct. 2 - Starter motor condition - it is likely that after so many years there is wear in the starter motor that slows its speed. Critical to cold starts. 3 - Battery - if it is nearing the end of its life or wasn't rated properly to begin with, it could be the cause of slower starter motor speed. 4 - Wiring - failing wires and/or the connections could result in reduced power to the starter motor. If evaluation and correction of the above doesn't give the results you want, the symptoms are those of lowered compression. A compression test, made with the proper tester, can confirm this. You may even want to do this before trying to set the injection timing.
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