diesel fuel in the 851D's crankcase.

Off Road SHO · Mar 19, 2019

I picked up an early 60's 851 just for chance that the engine being relatively good. The PO said it just failed to start one day. The first thing I checked was the oil and saw that it had really clear, overfilled and diesely smelling oil. Now that I've cleaned all the crud off of it, where would be the first place I should go looking for the source of the fuel? Stuck injector? Or bad seals in pump?

Thanks in advance for any helpful hints.

Tom

showcrop · Mar 19, 2019

The easiest therefore for me the first place to look is the return lines under the valve cover. You don't need to remove the tank to remove the valve cover, you just roll it out. That is why the top of the cover is rounded. Second is umbrella shaft seals under the pump. Many people have trouble with them, but with abundant oiling and gentle massaging they go right in.

Dieseltech · Mar 19, 2019

If the weight retainer flex ring is failing inside the injection pump like most pumps I see in for repair the small coffee ground like bits will cause lower drive shaft seal trouble, and just changing the seals won't do any good. On my 871 the return line nut was loose in the cylinder head, return line fuel was seeping past the rubber grommet.

diesel fuel in the 851D's crankcase.

Off Road SHO

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showcrop

Well-known Member

Dieseltech

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