Diesel fuel in oil

[Squanderbucks]

Not 100% sure about your particular engine but most times it is critical to put the injector pump back exactly like it was removed for timing purposes. Check your engine service manual if you have one or get one online from places like eBay. Often these are gear driven with the pump gear set to match the camshaft timing.

If so mark the engine somehow at the gear and mark the pump gear or shaft as well.

[GoneIsland]

Mike is correct on this one. We had the same problem with our 4108 and had to have the hp pump rebuilt by a shop. No clue about where you can have it done in your area but any diesel repair place will know. Hard part about this job is the damn 3rd bolt. It's a pain to get out and back in when done. I had to tape together some socket extensions and the socket after dropping in the bilge several times. Make sure to line the timing marks up the way it was when you took it off, pictures help. Oh and label everything when taking apart or phone videos before to help it all go back on smoothly.

[GoneIsland]

Found a picture of the timing mark when I took the hp pump off.

[jewt]

I had the same problem with my Perkins 4-108M but mine filled the crankcase and overflowed into the air breather causing a runaway engine till I slap a board over the intake. The problem was with the high pressure pump leaking.
Only time I ever saw a 108 hit 4k RPM.


jewt

S/V Bifrost

[shanegeard]

Originally Posted by GoneIsland

Found a picture of the timing mark when I took the hp pump off.

Thank you

[shanegeard]

Originally Posted by Squanderbucks

Not 100% sure about your particular engine but most times it is critical to put the injector pump back exactly like it was removed for timing purposes. Check your engine service manual if you have one or get one online from places like eBay. Often these are gear driven with the pump gear set to match the camshaft timing.

If so mark the engine somehow at the gear and mark the pump gear or shaft as well.

Thanks

[shanegeard]

Originally Posted by jewt

I had the same problem with my Perkins 4-108M but mine filled the crankcase and overflowed into the air breather causing a runaway engine till I slap a board over the intake. The problem was with the high pressure pump leaking.
Only time I ever saw a 108 hit 4k RPM.


jewt

S/V Bifrost

I was warned about the runaway engine phenomenon. My 4108 has a mushroom air intake. Apparently one of the few solutions is to squirt a fire extinguisher into the vent.

[GoneIsland]

DO NOT use a fire extinguisher! Lord knows what that would do to the guts of the motor. Pull the mushroom cap off and put a board over the intake. Don't use a rag either cause it will just suck it in.

[shanegeard]

Originally Posted by GoneIsland

DO NOT use a fire extinguisher! Lord knows what that would do to the guts of the motor. Pull the mushroom cap off and put a board over the intake. Don't use a rag either cause it will just suck it in.

Yes I wondered about that. Praying it never happens.

[Lepke]

The most common path for fuel into the oil is the injector pump seal.
There is little residual pressure in the injectors and the volume of injector lines is small. At most a few drops. If all injectors leaked less than an ounce.
If an injector tip failed, when running you'd have black smoke.

[Jesse]

If you use a fire extinguisher to stop a runaway be sure it's CO2. Are you using a day tank or is your fuel level above the injectors? If not there is a possibility that someone is messing with you. Limited amounts of fuel can pass through an inactive pump but not through injectors that are above the fuel level. When you replaced the lift pump did fuel flow from the supply line? If not, wait for the expensive work on the injectors and injector pump because the problem is somewhere else.

[ctl411]

I had the same problem with fuel in oil. Front seal on hp pump was bad along with shut off shaft seal. Honestly if you can remove and replace the pump yourself you can reseal the pump. My 4-154 had a "alignment" bolt on the front cover that you back out into a hole on the back side of the front crank pulley. This prevents the engine getting turned by accident. Make sure to mark hp pump before removing.

[shanegeard]

Originally Posted by Jesse

If you use a fire extinguisher to stop a runaway be sure it's CO2. Are you using a day tank or is your fuel level above the injectors? If not there is a possibility that someone is messing with you. Limited amounts of fuel can pass through an inactive pump but not through injectors that are above the fuel level. When you replaced the lift pump did fuel flow from the supply line? If not, wait for the expensive work on the injectors and injector pump because the problem is somewhere else.

Thanks, I'm the only one on the boat so no pranksters involved! And whilst the fuel tanks are above engine level it does have a lift pump (just replaced along with gasket)

[shanegeard]

Originally Posted by ctl411

I had the same problem with fuel in oil. Front seal on hp pump was bad along with shut off shaft seal. Honestly if you can remove and replace the pump yourself you can reseal the pump. My 4-154 had a "alignment" bolt on the front cover that you back out into a hole on the back side of the front crank pulley. This prevents the engine getting turned by accident. Make sure to mark hp pump before removing.

Thanks, will make sure it's correctly aligned.

[svthreecheers]

Originally Posted by stewie

I have had the same problem and it was the seals on the injector pump. You can change these yourself just google injector pump seals. Although how diesel is getting in there when the engine is not running baffles me. Best of luck.

your right stewie
it is the injection pump front driveshaft seal thats leaking
during operation the housing pressure insite pump puts pressure
on the outer seal lip and keeps it from leaking
when engine shuts down the worn seal outer lip collapses and drains
the diesel from the pump into the engine oil
usualy causes hard starting due to air in the system