Ford 961 Diesel problems

Mike Lumley · Jul 16, 2013

Recently had my motor rebuilt on my Ford 961. After getting it back and using it for awhile, it has become very hard to start and even at times won"t start at all. Other than compression test, making sure injectors are delivering fuel and pump is in time. what other possible causes should I look for?
Thanks

Texas! · Jul 16, 2013

What do you mean by "hard to start"? It won't turn over (crank) or it cranks but won't start? When it won't start do you go back later and try again and it starts then? If it cranks but won't start do you see any smoke coming out of the exhaust?

showcrop · Jul 17, 2013

Cranking speed is very important. I was having trouble with mine with only about 300 hours on rebuild and freshly rebuilt pump and injectors. Finally I pulled the starter and found bronze powder on the end. After rebuild and ten seconds preheat it always fires up in about one second. battery and connections need to be A+++ as well.

Mike Lumley · Jul 17, 2013

It cranks, there just isn't any ignition.

Frank Beights · Jul 17, 2013

My 941 did this awhile back and after checking every thing three or four times we finally found the pressure relief line blocked. That's the very small line from the injector log back to the bottom of the fuel tank. After this was cleared didn't have anymore trouble until I had to have the injector pump rebuilt. It was leaking fuel into the crankcase.
Frank

Texas! · Jul 17, 2013

Of course there's no ignition- you said it's a diesel. When it's cranking over is there gray smoke coming out of the exhaust? If there is you're getting fuel into the cylinders but it's not getting hot enough to burn. It's not getting hot because you either have low compression, slow cranking speed or the cold engine block is soaking up the heat in which case you need to use the manifold heaters which are 2 devices that look like spark plugs screwed into the intake manifold or you need a block/water heater.

Mike Lumley · Jul 17, 2013

As in ignition I meant running. I know there arent any plugs. Going to check compression

showcrop · Jul 17, 2013

(quoted from post at 17:06:34 07/17/13) As in ignition I meant running. I know there arent any plugs. Going to check compression

Check easy things first!!! way easier to check cranking speed as Texas and I are trying to tell you and also much easier to check the return line as Frank Bight suggested. Also consider the likelihood of a problem. Low compression should be highly unlikely because you stated that you just got it back from a rebuild. How about taking a piece of paper and making a list of what was and what was not renewed in the rebuild and concentrate on the nots instead of the wases.

Hal/ Eastern WA · Jul 17, 2013

Did you try a new fuel filter yet?

Ford 961 Diesel problems

Mike Lumley

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Texas!

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showcrop

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Mike Lumley

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Frank Beights

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Texas!

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Mike Lumley

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showcrop

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Hal/ Eastern WA

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