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lawsonmitchell 07-19-2013 02:01 PM

Yanmar 1GM10 won't start.
The usually reliable 1GM10 on my boat suddenly won't start. One day fine, today... no starting. I have ruled out the following:
Fuel filters
Fuel supply
Fuel system properly bled
No blockage in air intake
No blockage in exhaust

Fires briefly with starter fluid in air intake...
(I assume that means compression is OK)

Help, racing on Sunday. I do not feel like paddling in and out of the marina.

arf145 07-19-2013 04:46 PM

Re: Yanmar 1GM10 won't start.
I don't know that starter fluid means it has enough compression for diesel or not. So you've verified that fuel is spraying out of the injector?

lawsonmitchell 07-19-2013 05:49 PM

Re: Yanmar 1GM10 won't start.

bljones 07-19-2013 05:58 PM

Re: Yanmar 1GM10 won't start.
If she'll start with starter fluid but will not remaining running, you haven't completely bled the lines. folow the bleeding instruction in the manual to the letter. and then do it again.
and then do it again. these things can be a bear to bleed, especially if you have replaced the filter without clamping off the lines.

larrytwo 07-20-2013 01:31 PM

Re: Yanmar 1GM10 won't start.
You may want to check the mixing elbow ( where the water cooling is injected into the exhaust.) if it is corroded it well allow water back into the cylinder and the engine won't start. I've seen this... :-) good luck.

smurphny 07-20-2013 06:51 PM

Re: Yanmar 1GM10 won't start.
+1 on rethinking your theory about it not being fuel. There are 2 bleed points on my 3GM. The one on the injector pump is not obvious. Ether is really bad for these little diesels, so the less you use it the better. You also need to be careful of hydrolock from cranking too much. Any miniscule air leak from fuel tank to injector will cause it to not start.

arvicola-amphibius 07-20-2013 09:25 PM

Re: Yanmar 1GM10 won't start.
Have a read of other threads here relating to 2 GM and 3 GM as they all work fairly much the same way; can all be a bit tricky to start in very cold weather. Work through one issue at a time. Check for something really simple to begin with, like the decompression lever (or a valve) stuck open. That one will be obvious because you will be able to spin it over by hand.

While you are messing around cranking it over, keep the seacock CLOSED because if you haven't yet got water in the cylinder you sure don't want to add that to your woes. Just remember to open it as soon as the engine does fire up.

JimsCAL 07-21-2013 08:41 AM

Re: Yanmar 1GM10 won't start.
I agree it sounds like a fuel issue. Also sounds like this didn't occur after a maintenance activity like changing a fuel filter. Air in the system would seem to be the most logical issue. And you got good advice about keeping the water intake seacock closed while cranking. You don't want to get seawater into the engine.

lawsonmitchell 07-21-2013 11:58 AM

Re: Yanmar 1GM10 won't start.
Definitely getting good fuel all the way to the good injector. No air. Still stumped.

arvicola-amphibius 07-21-2013 09:12 PM

Re: Yanmar 1GM10 won't start.
Go to the other thread on Yanmar starting and try the technique of warming it on compression then using full throttle. If that won't start it, then look for something else. Diesels rarely run perfectly one day and fail the next, so don't fear the worst just yet. Possibles:

Fuel is contaminated - high pressure filter (the one on the engine) partially blocked
Air intake is blocked (the foam self-destructs over time)
Fuel shut-off is stuck in shut-off position or the cable has come adrift from the arm on the FCU
Valves stuck open - maybe due to slight mis-rig of the decompression lever - a 'love tap' with a rubber hammer on the rocker cover could be the fix for this, otherwise pull the rocker cover and see if the valves are moving through full range as you crank it.

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