Yanmar 2GM20 Started, Idled too low, won't start

[sonsets]

Perfect! Your suspicion was correct. Mine was more of a break-in manual and the link you supplied is the rocket science variety. Now, if I can just find one for the Hunter 28.5.

Thanks, I really appreciate everybody's time and comments.

[Tellie]

You're gonna be an old hat at this in no time. If it ran great before it will run this way easily again. Check for a fuel priming lever next to the fuel pump. You may have to pump this a good bit as well.


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[philtrick]

Originally Posted by sonsets

Perfect! Your suspicion was correct. Mine was more of a break-in manual and the link you supplied is the rocket science variety. Now, if I can just find one for the Hunter 28.5.

Thanks, I really appreciate everybody's time and comments.

Maybe here will help:
Index of /wp-content/themes/marlowhunter/export/Owners-Manuals

I know it says export, but my manual lists the differences for the USA/Export models

HTH,
Phil

[QB Cruiser]

agree bleed air and use the small lever on fuel pump(starboard side of engine) to pump fuel out thru loosened bleed screw at top of fuel filter on engine (stbd fwd side) . I installed a Racor filter with a pump on it on the line from the tank so that i could more easily pressurize the fuel line to the engine and bleeding is easier. Also check that 2 blots holding fuel pump are tight and agree with need to periodically check the banjo bolts as they can leak fuel .... great little engine tho...good luck

[fuentes]

I am with the "air in the system" group. Begin by manually pumping diesel from the diesel tank into and through the first filter. Do this until there is no air coming out from the bleeder bolt on top of the filter unit. Continue this progressing through each filter (if there is more then one) until you reach the low pressure pump. Open bleeder or, bleeders if more than one at the low pressure pump, one at a time progressing toward the high pressure pump. Make sure pure diesel squirts out. No air. Then loosen nuts on each injector making sure pure diesel squirts out. For this you will need to turn the engine. You will need help with someone cranking while the other observes the diesel squirting out. Ones all this is done. It should run. It might take more then ones of doing the whole thing. If it runs but later will not, check to see if air is coming into the system by doing all this again. If it is, check to see where. Seals at filters. Bleeders not sealing. Cracked fuel line somewhere. After you do this for a while you will know your system and have a feel for it. Have a nice day. Hector

[a64pilot]

Originally Posted by sonsets

Dumb question. Since this has always started immediately, and did so today, can you flood a diesel like you can a gas engine?

Short answer is No.

You need to become familiar with bleeding the fuel system, after you do it a few times it will be like tieing your shoes. You will need to bleed anytime you open the fuel system, like change a hose or something, most common is to change a fuel filter

[Dulcesuenos]

Air in the fuel system can happen at any time and it can be one of the most frustration things. It could be a pickup tube, fuel line, filter seal primary or secondary. Connection at a lift pump, lift pump diaphragm, bleed valve washer or gasket etc etc. And just because air gets in doesn't mean fuel gets out. Start at one end of the fuel system and work towards the other checking every possible thing.

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[a64pilot]

Originally Posted by sonsets

I just changed the filters and the fuel line was on.

This is why I think filters was the source of air, I don't think he knew to bleed after a filter change and it ran on the fuel in the pump for a short while, since he ran it dry that is going to be lots more bleeding than a simple filter change

[Compass790]

My tip is to ignore the little priming lever on the lift pump & just use the bulb to prime all the way to the injector pump inlet as it's faster & easier , otherwise nothing to add

[sailbocagrande]

I have seen the exhaust mixing elbow rust/soot up internally and cause too much back pressure for the 2 cyl yanmar to run and or start. Just a thought.

[lockie]

Re bleeding, there is also a bleeder at the inlet at the top of the injection pump. This does not get mentioned in the manual, and usually does not need to be bled. However I did need to bleed it once to get my 2GM going.


Cheers, Graeme

[boatbod]

Certainly you need to bleed the fuel system as far as the filter housing on the engine (metric bleed screw on top). You may or may not need to bleed the injection pump, which is easiest accomplished by cracking (backing off) the hard lines to the injectors and cranking the engine. Re-tighten as soon as fuel appears at the injectors.

[fwilmeth]

I spent years 20 years with a 2GM20 on the west coast. I'm not sure where you are. I will assume salt water. An annual maintenance item for these engines is the exhaust port which attaches immediately behind the head (not fun to get to) but has an issue with clogging with soot produced by the exhaust of the engine. Once plugged, or almost so, the back pressure will prevent the engine from starting. You have not said, that I have seen, how many hours are on the engine. But before I began dismantling the fuel system I would check this exhaust port. Your description of the problem is pretty much what happens when it becomes clogged. It is held on by three bolts and, while difficult to reach at the rear of the engine, takes about 30 minutes to inspect.