Small Diesel Cylinder Compression Question

fpappal · Apr 12, 2021

Hello,
Does anyone know what the compression should be on a 13hp two cylinder diesel? The engine is a Mitsubishi KE70 and is on a 1980 Iseki. I am getting 380 lbs in one cylinder and 340 lbs in the other. Tractor will not start and I am wondering if the compression is too low. I realize it is not an antique, but it is 41 years old. I am getting those numbers from testing from the glow plug hole. This is an indirect inject engine.

Thanks

rustred · Apr 12, 2021

that is ok compression for a diesel and it should run with that. is there fuel at the injectors when you bleed it?

wore out · Apr 12, 2021

Compression seems reasonable to me for an indirect injection diesel with glow plugs. Are the glow plugs working? Does the engine smoke at all when you try to start it? Is it cranking as fast as it should?

Below is a link to a download (.pdf format) of the service manual for your engine. Looking it over quickly I did see a mention of compression but not a spec of what it's supposed to be.

Might be worth taking a look at.
Mitsubishi diesel manual

fpappal · Apr 12, 2021

Yes. Long story short. Was tilling with the tractor for 20 minutes and then the clutch failed. Brought it back to the barn and now it will not start. I get black smoke out of the exhaust, it sounds like it wants to, but it just won't fire. Even tried a little starting fluid. Fuel did not run dry, fuel filter is not plugged. Glow plugs are working as far as I can tell. When I crack the injector lines at the injectors fuel does come out. Not a lot, but it does come out. It never started easy, but now it won't start at all.

fpappal · Apr 12, 2021

I removed both glow plugs and jumped them with the battery. They both started to smoke so I am assuming they are working? Yes, I get black smoke while trying to start it. It sounds like it is cranking at the same speed it always has. I suppose it could be a little bit slower but not positive. Thanks for the pdf.

the tractor vet · Apr 12, 2021

A glow plug needs to do more then Start smoking as it SHOULD GLOW in around lets say 10 seconds .

Steve@Advance · Apr 12, 2021

If it is making black smoke, it is trying to run.

Is it possible something is holding it back, like a loaded hydraulic pump?

Steve@Advance · Apr 12, 2021

I saw you checked the glow plugs, but did you check for voltage to them installed and wired to the tractor harness?

wore out · Apr 12, 2021

(quoted from post at 12:52:39 04/12/21) If it is making black smoke, it is trying to run.

Is it possible something is holding it back, like a loaded hydraulic pump?

MOST EXCELLENT suggestion, Steve!

I have seen exactly that happen.

fpappal · Apr 12, 2021

I did check the voltage at the glow plugs installed. I think they were around 10V. Good question about hydraulic pump. The tiller is currently up. I didn't want to lower it in case I had to move the tractor. It has always been in the down position every time I have ever started it until now. Worth a try, thanks!

fpappal · Apr 13, 2021

I found the specs for the engine. It says that if the compression drops below 370 lbs it is time to rebuild. Normal pressure should be 455 lbs. I will check the compression again but it looks like the one cylinder might be a little bit on the low side.

Small Diesel Cylinder Compression Question

fpappal

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rustred

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wore out

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fpappal

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fpappal

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the tractor vet

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Steve@Advance

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Steve@Advance

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wore out

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fpappal

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fpappal

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