Yanmar 1GM10 fuel pump

[Ddec34]

I am working on this engine and I know very little about them. When the owner called me, he had changed the lift pump and had fuel going to the injection pump, but it would not start and it sounded like the engine wasn't getting fuel. I cracked the line at the injector and there was no fuel getting to the injector. The owner found a used injection pump and I installed it for him. We now have fuel at the injector and when we turn the engine over, when the engine tried to fire the engine tries to lock up and slows way down. I think the timing is off, way advanced....or the starter is very weak and turning over too slow....any ideas??

 

[earlybird]

Make sure that the battery is fully charged. Yanmar GM series aren't the best starters in cold weather. Also you might try temporarily removing the alternator belt to reduce drag on the engine if it does try to start.
I wouldn't fiddle with the injection timing until all else fails., but it could be checked if you have access to a workshop manual for the method.

 

[RichardS]

Make sure that the battery is fully charged. Yanmar GM series aren't the best starters in cold weather. Also you might try temporarily removing the alternator belt to reduce drag on the engine if it does try to start.
I wouldn't fiddle with the injection timing until all else fails., but it could be checked if you have access to a workshop manual for the method.

+1

It might need a new battery?

Richard

 

[Ddec34]

Make sure that the battery is fully charged. Yanmar GM series aren't the best starters in cold weather. Also you might try temporarily removing the alternator belt to reduce drag on the engine if it does try to start.
I wouldn't fiddle with the injection timing until all else fails., but it could be checked if you have access to a workshop manual for the method.

I pulled the compression release to get some speed while cranking, then as soon as I released the lever, I had ignition, but the engine seemed to temporarily stop like it was fighting against itself.....the weather here is a pleasant 70 degrees

 

[LiftyK]

Any changes to the alternator? The 1GM10 alternator uses a bigger, easier to turn, pulley than its larger brethren. If you have a replacement “pattern” or “copy” alternator it will have the smaller pulley which is harder to turn. I appreciate that you did not mention anything about an alternator but the engine stumbling to pick up after it fires is exactly what I had when I installed an incorrect replacement alternator on my 1GM10. Whatever the fault, be aware that the 1GM10 only just has enough power to get going when cold. Earlybird’s suggestion to disconnect the alternator sounds like a very good thing to try.

 

[Topcat47]

Any changes to the alternator? The 1GM10 alternator uses a bigger, easier to turn, pulley than its larger brethren. If you have a replacement “pattern” or “copy” alternator it will have the smaller pulley which is harder to turn. I appreciate that you did not mention anything about an alternator but the engine stumbling to pick up after it fires is exactly what I had when I installed an incorrect replacement alternator on my 1GM10. Whatever the fault, be aware that the 1GM10 only just has enough power to get going when cold. Earlybird’s suggestion to disconnect the alternator sounds like a very good thing to try.

+1 re the alternator problem. My chinese copy replacement did not accept the original pulley, even when a "correct" diameter pulley was fitted, it demanded more power than a cold 1GM10 could produce. Tests later showed it was twice the power of the original Hitachi.

They are a b&$£@&D to start in cold weather, too. It helps to run it up with the decompressor open and the throttle shut to get some oil around the engine before Starting it properly.