Detroit 2 stroke in Clark skidder - fuel getting into crankcase

[wdncno]

A friend of mine has a Clark skidder with a Deroit deisel- not sure if it is 3 or 4 cyl. about 80 hp.  The engine has just been rebuilt and has lots of power.  He is getting fuel in his engine oil.  Any ideas where to look. thanks

[Jeff]

We had that problem in a 404 timberjack. Was a cracked fuel jumper line under the valve cover.

[Jeff]

I reread my post and it makes it look like I meant a broken line. When I said cracked, I meant it had been loosened (cracked open) and not tightened back up properly.   That old detroit, when it was run out of fuel, you would have to crack open the lines to the injectors bleed them to get it to go again. The time we got fuel in the oli was after the skidder running out of fuel and then the bleeding procedure being done, and a line not getting tightened back up.  The next morning when the oil was checked it had way more then it had the day before.

If this is a new rebuild, check for a loose fuel jumper.

[Ed_K]

 80 hp its a 3 cyl my 453 has 136 hp. I think it may be due to not seating the rings yet. or like Jeff says check the lines. Mine is close to being wore out and it get fuel into the oil when i let it idle a long time.
Change to oil an watch to see if it happens again. I try to change mine every 200 hrs.

[John Woodworth]

Is he blowing black smoke when he opens the throttle'if so could be with the injectors, should use N45 injectors set at1.460 so if it isn't leaking lines or too much fuel pressure i'd sure check the injectors.

[John Woodworth]

Another thought, how has he been running it to break it in? if he's been running it against the governor from the start it probably is with the rings. I've broke mine in 25%-50% 75% throttle with loadin stages and had no problem.

[timberfaller390]

Break in is very important with a new motor. on gas burners about half the crowd says break it in nice and liesurely, and the other half says put a load on it and go. My grandpaw (mechanic by trade) always said to "break em in how they are going to be used". So if it was a truck load it up and and find a few mountains to go up, if it was a car hit the interstate and if it was a tractor sink the plow in the ground and let 'er eat. We always put 500 miles on the vehicles before we considered them broke in.

[wdncno]

Thanks- I'll tell him to check under the valve cover. It has been broken in- rebuild was last spring.- Michael

[Busheler]

Crack the injector lines while it's running and make sure you hear a change in rpm on everyone you crack.  I've seen high compression seals in a injector pump crack and allow fuel by.  It will leak internally in the pump and get back in to the oil rather than build enough pressure to push the fuel out of the injector.  If when you crack one it doesn't change sounds, then you know that injector is not working.  If you find this is the case you can always eliminate the injector by swapping it with the one beside it.  If it still does the same thing................it's the injector pump.

[wdncno]

Thanks guys- it was the injector pump- turnedi up way to high- he had awsome power, but to much fuel was going through and some was end up in the crankcase. has been fixed