Suzuki DF140 Making oil- tried everything I think

[srowejr]

I have a 2002 Johnzuki 140 (df140) with about 150 hours on it. Bought it used and it is making oil. Smells like gas in the oil. It will make about 1/2 to 1 qt of extra oil in a afternoon of running hard, no trolling.

I have done the following:

New Low Pressure fuel pump, replaced seat, needle and screen, checked float height (was fine) and cleaned VST -wasnt really dirty. Changed thermostat to 160 degree model, had the injectors cleaned and tested for leakage, tested fuel pressure to the rail and was on spec.

I guess its always possible that the NEW Low Pressure fuel pump is faulty, - I tested the new pump by taking it off the block and squeezing the bulb and did not see any leak around the piston.

Otherwise, is there ANYTHING I might be missing? I find it hard to believe that I can reach top RPM, no smoke in exhaust, and that much fuel is blowing by the rings due to them not being seated.

Any help PLEASE? Thanks in advance!

[Greg Moore]

I thought that was a Yammy trick.. Have you done a compression test? No fixing it from the outside if compression is gone. Low pressure pump should have no impact on this, it simply supplies a float bowl the high pressure pump draws from.
What colour are the plugs after a run? Either you're squirting too much fuel in (plugs will hint to that) or your compression rings are shot. Oil scavenge rings maybe OK so you're not burning oil, but if compression rings are gone you'll get too much blow by. If you can segregate the vent pipe (no clue where on your motor) from the intake and hook a length of hose to it into the boat where you can see it. Take it for a run and see how much flow is coming out the vent pipe, if it's coming out like a blower hose you know where you're headed.

[srowejr]

Plugs look really good. I guess... no black soot no overheated ceramic around the electrode. Really clean. I will try running it with the VST vent pipe disconnected and extended like you suggest... Can I do that on the trailer or is it best to do it under load? I tried that for about 10 mins on the trailer and did not get anything through the hose should i run it longer on trailer?

Thanks!

[Harper]

I thought that was a Yammy trick.. Have you done a compression test? No fixing it from the outside if compression is gone. Low pressure pump should have no impact on this, it simply supplies a float bowl the high pressure pump draws from.
What colour are the plugs after a run? Either you're squirting too much fuel in (plugs will hint to that) or your compression rings are shot. Oil scavenge rings maybe OK so you're not burning oil, but if compression rings are gone you'll get too much blow by. If you can segregate the vent pipe (no clue where on your motor) from the intake and hook a length of hose to it into the boat where you can see it. Take it for a run and see how much flow is coming out the vent pipe, if it's coming out like a blower hose you know where you're headed.

I think you're mistaken on both approaches. In the first place I believe the low pressure fuel pump is a cam operated diaphram pump. If the diaphram tears, the fuel goes right to the crankcase. Secondly, compression rings being shot would of course cause crankcase pressures, but should have no correlation to raw fuel entering the crankcase. Srowejr is making way too much oil to be caused by anything other than a direct leak of raw fuel into the crankcase. Raw fuel from somewhere other than the combustion chambers.

That said, srowejr, only thing I can think of is for you to recheck what you've done. I would have checked the low pressure pump for leaks by removing it, and while blocking the outflow of the pump, actuate the pump plunger by hand. Try to duplicate how the pump actually works and see if you detect any leaks. You basically did a static check for leaks. You might find that a dynamic check will yield different results.

[srowejr]

Great point. Thank you for the info on testing the LP pump. I will try activating the plunger to see how that behaves.

This is really stumping me...I have to be close.

[redlowrey]

I think you're mistaken on both approaches. In the first place I believe the low pressure fuel pump is a cam operated diaphram pump. If the diaphram tears, the fuel goes right to the crankcase. Secondly, compression rings being shot would of course cause crankcase pressures, but should have no correlation to raw fuel entering the crankcase. Srowejr is making way too much oil to be caused by anything other than a direct leak of raw fuel into the crankcase. Raw fuel from somewhere other than the combustion chambers.

That said, srowejr, only thing I can think of is for you to recheck what you've done. I would have checked the low pressure pump for leaks by removing it, and while blocking the outflow of the pump, actuate the pump plunger by hand. Try to duplicate how the pump actually works and see if you detect any leaks. You basically did a static check for leaks. You might find that a dynamic check will yield different results.

........good to see someone on the right page

[srowejr]

So I tested the LP fuel pump by actuating the piston and it is tight as a drum. Not sure where to go from here.

[Harper]

So I guess that takes you back to the VST. Can you remove the vapor line temporarily from the VST and put another line in its place that will vent externally, say to a can or something, so you can see for sure that there is no liquid fuel being discharged while running?

[srowejr]

Yep. That's what I will do. Ran it for 45 minutes varying the Rpm on the muffs today and not a drop out the vent hose. Did have some oil droplets come out of the nipple that the vent hose connects to as it was running. Again not sure what that means if anything. Whatever is happening it sure seems like it must be happening under load.

Just FYI, checked the compression today from top to bottom, top being 1, the top 3 cylinders were spot on 215psi while the bottom was at 220. So does not seem with that type of compression that blow by would be an issue.

Thanks for the help guys. I will absolutely report back with my findings! In the mean time if anyone has any other ideas, let me know.

[redlowrey]

You pulled the small pipe off the cam cover not the big one right

[Seaduck]

Damn bud you are doing everything I could think of. My 07 df115 had fuel coming through the vent hose. That's where my problem was. Once I fixed that issue it hasn't had a problem since. Hope you figure it out!!

[srowejr]

Yep it's the small hose.

[srowejr]

I hope so too! I hope I see it under load, but honestly, I don't anticipate that making a difference. Gonna try though.

[redlowrey]

Run the engine on the muffs at idle for half an hour and check the vent line if the float is not holding its level fuel will soon come out the pipe running the engine hard might be consuming the fuel faster than its rising

[srowejr]

I have run it at idle for 20mins and no fuel and at about 1100 for 44 mins and no fuel out of the vent line.

I had a thought, if the ecm isn't closing an injector then it would dump fuel. I know the injectors are good, but how could I test them on the engine?

Could I pull the rail with the injectors on it and turn the key to see if any leak? Any ideas about that?

Thanks guys!