Fuel Mixed w/ Oil in crank case

[Kwaj]

I am new to this forum and have been reading your posts for the last year and many of them had helped me, thanks for all poster's.
I have twin F115 EFI on a Glacier Bay 26ft. My port engine is gaining oil and my first respones was to replace the mechanical fuel pump that is on the valve cover but I am still having the same problem. Two months ago I removed the fuel injectors and cleaned them, the engine had lost power and this cleaning did the trick. But three weeks ago I had to replace #4 injector it got cloged up agian and now I have the fuel/oil problem. I have two racors and the filter on the engine are clean. All filters get replaced every 100 hours, as do the oils.
Any help would be well appreciated,

 

[Dunaruna]

Re: Fuel Mixed w/ Oil in crank case

Different replacement filters are available to help cope with poor quality fuel (ethanol), check to see if your filters are 10 micron or better.

 

[Kwaj]

Re: Fuel Mixed w/ Oil in crank case

The filters are 10 micron filters, I made sure of that. I live in Kwajalein, Marshall Island on an Army Base and the quality of the fuel is not very good. The engines that have a Carb. run ok with this fuel but the EFI's are always having problems. We also have a problem with water in the fuel and run the racor's. I did a compression test all cylinders have 165psi. I removed the injectors/fuel rail, installed them to a cut down intake so they would stay secure. Pressurized the fuel system and checked for any leaking injectors. I did not see any leakdown. Maybe they leak down only when hot, i will try that next.
Any help or ideas would be appreciated

 

[TOHATSU GURU]

Re: Fuel Mixed w/ Oil in crank case

Your fuel in the oil is probably from the engine not maintaining operating temperature. It is considered normal for a four-stroke outboard engine to suffer from this to a certain extent. Change your oil every 50 hours and avoid idling when possible.

 

[rodbolt]

Re: Fuel Mixed w/ Oil in crank case

in the mashalls I doubt cold weather running is much of an issue .
however you still need to verify the engine operating temps are correct.
another quirk of EFI is overpropping.
if that engine cannot hit 5800+ RPM at its normal load it WILL make oil.
on most fourstrokes we find compression tests to be just about useless,you need to do a leakdown test.
check with the guys in the air corps section one should have a leakdown tester.
if these are US market motors they may be under an update for some things. without a model number I cant tell.
there is also a fuel filter upgrade for some of the older engines to add a 10 micron inline filter between the fuel pump and the VST.
why cut up anything? a fuel rail pressure test can find leaking injectors as can simply reading the plugs.
and yes poor quality fuel can lead to making oil as it simply wont burn correctly.
carbed motors rely on intake vacum and barometric pressure to move fuel.
anything that affects either will alter fuel flow.
EFI doesnt rely on either to move fuel.
35 psi on the rail and a pulse on time at the injector and fuel is now in the intake regaurdless of what is actually happening in the engine.

 

[reeldutch]

Re: Fuel Mixed w/ Oil in crank case

rodbolt why do you say a compression test on most 4strokes are useless?

when we winterize an engine or a tune up, we always even if the engine is running great, check compression.
i know it wont tell you what the problem might be bud you might get an indication something is going on.
we have succes on jetski's 4 stroke yammies wich had a low compression cylinder so we gave it a good decarb changed the oil and the engine has great compression again.

why do you think that it is useless?
and if there is a problem still after the decarb we will get the leakdown tester out.
its just a routine we do.
let me know what you think

Reeldutch

 

[rodbolt]

Re: Fuel Mixed w/ Oil in crank case

why I say its useless on most 4 strokes.
most high performave 4 strokes use a relativly tight piston to wall clearence and dont pin the rings.
in the case of an EFI 4 stroke if the rings line up it makes oil rapidly and WONT show up on a compression test.
couple that with the fact I am lazy and poof.
case of thge F115, for that simply remove the plugs,rotate the flywheel to TDC #1. then attach the leakdown tester. if leakage is close to 100% then go to #4 as #1 has an open valve most likly.
from there simply folow the firing order and rotate the flywheel.
if leakage is within spec I am done with that mechanical check without ever getting in the hull.
if #1 is exhausting the #4 is TDC compression stroke.
same as 2 and 3, if one is on exhasut stroke then the other is TDC compression stroke.
not rocket science and can be done in 10 minutes or so by one tech wthout removing a lot of stuff or hunting down the jumpit pack.
on the jet skis, like the 8.1L GM motors, the timing marks arnt easy to see and most times dont exist and there is no distributor to aid in finding TDC.
miss TDC by a few degrees either way and the engine rotates instanly when air is applied.
but its what I hammer on all the time, if there is a running issue the first point is to verify can the cylinder be sealed?
however in the case of making oil I want a quick check on if the rings are leaking or hunt a different bunny.

 

[Kwaj]

Re: Fuel Mixed w/ Oil in crank case

I have found the problem, it was human error. I am Engineman for Marine Police and in charge of five boats. I have two helpers and they are part of the crew also. My well intentions man checks the oil every morning as part of our presail of all the boats. He has been tilting the engines down and imidiatly checking the oil. It is low so he would add a little oil and not recheck it. He had me convinced of fuel in the oil, this was also my mistake also.
I did do the leak down test, all was good. But I also did a running compression test, which i used to do on cars when i work on them. This was an easy and quick test. Do do a running compression test you must disable the fuel injector and ground the coil wire. Run the engine and compare all of your results.
Thanks agian Gentelmen for your help