Y112 on Propane Won't Start Warm

I have a forklift with a Continental Y112 motor, Impco Model J evaporator and Impco CA50-64 carburetor.

It runs great but will not start once it is warmed up. Once it cools down it starts again. I had to replace the head gasket last year so I am pretty sure that the head is in decent shape and there was no bad wear on the cylinder walls.

I have had the ignition timing all over the map without much effect.

Any ideas about what the problem could be or things that I can try?

Thanks,
JP.

I'd give 'er a compression test.

Allan

Won't argue with Allen as his advice is good as always.

I would add that I woud be guessing that a pursuit of ignition troubles would be a good idea. The condensor or coil would be my first suspicions as the culprit.

If you have a spark tester do a check with the engine warm.

hth

jt

I'll rig up an adapter for my diesel compression tester and give her a go. What should I see on that motor?

I've never changed the condenser or coil on that machine so I will now.

Thanks guys,
JP.

If you haven't already changed the parts replace the capacitor then the coil. Don't shotgun it but make it a learning experience by comparing the symptoms of each. Check the points for indications of arcing. That's an indicator of capacitor trouble. A little know fact, it seems, is that when on engine is shut down it gets hotter because the cooling system stops working. That may be all it takes to trigger a marginal component to fail.

I had a little Clark lift a while back that had something similar going on but it turned out to be fuel related instead of spark as I had replaced every ignition component.

Next to the regulator was another valve that looked almost like it that actually turned the propane on and off via engine vacuum it had gone bad. I replaced it with an electric solenoid and has been starting great ever since.

The compression hypothesis doesn't make sense to me. I don't recall ever working on a worn engine that had less compression when it got hot. It's usually the other way around - low when cold, and higher when warm. That - except one situation that comes to mind. An overhead-valve engine with the valve-lash adjusted too tight. They will get even tighter when hot - and in that case - compression will go down after warm-up.

I'm not up to speed on all the different propane systems - but there are several. I've known of many that developed "hot start" problems - and most of the problems were caused by the fuel-controls.

I just recently witnessed a guy getting screwed on a "low compression" diagnosis on his Red Seal powered forklift. I was asked to go down and help out. It is propane powered. It started getting real hard to start. The guy took it to an auto-repair shop. They told him the engine was worn out - and they then bought a new Red Seal "long block" from Caterpillar. Well, they installed the new engine, and swapped over all the external parts - propane suff, carb, etc. And guess what - no start. When they got all done, it was one of the LP controls.

If I put a gauge on the "test port" of the propane evaporator how many psi should I have there? I'm a little suspicious of the gas system too.

There always seems to be lots of spark.

The continental Y112 is a flat head, valves are in the block.

Thanks again,
JP.

If your system was like the one I had and the evaporator works off engine vacuum, I tested that one with just my handheld vacuum pump at the port where the line slips on, it would not hold any vacuum at all.