Fuel in the oil

[ppags]

Hello all, Have a Yanmar 1300, Just finished installing an FEL and went to Op check it. Motor started fine but noticed fluid leak out of rubber hose by injector pump. Shut engine down and checked oil level and it is high. Tractor sat for about three weeks, did not shut off fuel valve. How is fuel leaking in the oil from just sitting there? As always, thanks for any help!

 

[Car Doc]

The only thing that comes to my mind is the pump must have an internal leak but I could be way off someone that really knows will be along to tell you. :thumbsup:

 

[winston1]

3 different fluids could invade the crankcase. Diesel, coolant or hydraulic/transmission fluid. Can you determine what is getting in there?

 

[Car Doc]

as Winston said and the way to tell if its coolant is crack the oil drain plug if there is water in that will come out first long as it has sat awhile and hasn't run.

I am not sure on the specific gravity of diesel whether it sinks in oil but I am sure if its been run it will mix pretty well.

 

[California]

Would the smell of diesel or hydraulic fluid be obvious in a sample of crankcase oil?

 

[ppags]

I am eliminating antifreeze as well as hydraulic on the grounds that it would have turned the oil into choclate milk, I had been running it. The oil is light in color, I would expect it to be black like my cummins oil is. Hard to distinguish the smell 'cause it all smells like diesel around a tractor. been trying to figure out the relation to the overfilled crankcase and the drip out of the hose by the pump, any thoughts?

 

[clemsonfor]

I am eliminating antifreeze as well as hydraulic on the grounds that it would have turned the oil into choclate milk, I had been running it. The oil is light in color, I would expect it to be black like my cummins oil is. Hard to distinguish the smell 'cause it all smells like diesel around a tractor. been trying to figure out the relation to the overfilled crankcase and the drip out of the hose by the pump, any thoughts?

Are you referring to the crankcase vent hose? Mine i think is near the pump but cant remember, but i do have a 2000.\

If the diaphram is bad can fuel still leak by? I dont know. Was it at the correct level before?

Oil analysis can sell you what it is but that will cost $30 and prolly take 2 weeks?

 

[ppags]

The hose I am refering to is on the fuel pump, I checked all other fluids, and they were good, so, I did an oil change and will monitor the level after every use. I ran it after the oil change, no more fluid out of the hose, ran for about 15 minutes and oil level stayed the same. Oil Analysis is a good idea which I just might have to utilize if this happens again. Oil that I drained was extremely thin, still thinking it is diesel contamination. Wondering if the pump drive shaft has a seal that would allow this to happen if it went bad. Hopefully shutting the fuel valve after every use will fix this problem. I will let you all know what happens.

 

[Brake Weight]

If the fuel pump had bad seals causing diesel to leak by when not in use, wouldn't there be a loss of operating pressure? Thusly causing a decrease in power.

 

[YannyMan]

Not if it were only leaking under non running conditions.

 

[clemsonfor]

Not if it were only leaking under non running conditions.

Is that possible?

 

[Brake Weight]

Are the Yan Mar mechanical pumps a constant pressure centrifugal style pump or a positive displacement piston type pump?

 

[California]

One piston per cylinder.

 

[YannyMan]

Is that possible?

If the engine still held a vacuum when off and the seal that was leaking was only doing so at rest, then yes.


Possibly a cracked injector housing?

 

[ppags]

Hey Guys, just an update, have about 4.5 hours since the oil change, have been shutting off fuel valve after every use, and no more issues. Still don't understand it, but I am not complaining!!

 

[YannyMan]

Sounds good. Sounds like a vacuum or cracked injector issue for sure.