Logo
FULL SITE MENU

fuel in oil - help

G

Gearobx Paul

New member
My 2006 DF140 has fuel in the crankcase oil. I noticed it last season after about 100 hours of running. When I did the oil change there was a noticeable smell of gas in the used oil. Hard to say how much gas was in the oil, likely 1/4-1/2 pint of gas in the oil (guessing) which is not very much after 100 hours of running. I checked the Mikuni low pressure fuel pump - there is no fuel coming out the back of the pump (where the plunger connects to the engine). I pressed the primer ball until it was firm and it stays firm. I pushed the plunger in/out and no fuel leaks out of the pump. I then disconnected the VST vent hose and ran the engine for at least 1/2 hour, until it was nice and warm. Ran at idle and at 3000 rpm. Nothing came out of this vent hose. The engine starts, idles and runs fine. I'm at a loss as to what to do next. Looking for some advice.
 
Lots of idling/trolling? Sometimes that’s the issue. It’s recommended to run it WOT to burn off fuel vapours that accumulate in the crankcase. I’ve also read the if the rings don’t seat properly on break in fuel can seep into the crankcase.

Not sure if manual pumping the low pressure fuel pump plunger is enough to test the diaphragm for leaks. I don’t know if there is a procedure to test the low pressure fuel pump.

My 2009 DF90A will “make oil” over the summer, watching the “oil level” closely I produce way less oil, if any, when the grandkids are up and all the boat does is pull water toys. Trolling will produce some “oil”. All the more reason the check engine oil regularly.
 
This is a stuck open thermostat. 100%
IVE HAD THIS 2X. I have twin DF 140 and service them on schedule, plus 3000 hrs. Anyways, change the oil and filter. Pull thermostat, it's easy, right on top. Put some grease around the mating surface, so when it fails again, it's easy to remove. Get the same or better thermostat.
 
Radman Dan said:
This is a stuck open thermostat. 100%
IVE HAD THIS 2X. I have twin DF 140 and service them on schedule, plus 3000 hrs. Anyways, change the oil and filter. Pull thermostat, it's easy, right on top. Put some grease around the mating surface, so when it fails again, it's easy to remove. Get the same or better thermostat.
Click to expand...
Thanks for the reply. When connected to ear muffs and running engine in my driveway, the water existing through propeller and tell tale is warm. I haven't measured how warm it is, but I would estimate 40C (104F) or higher. So thermostat likely is modulating. However, I haven't changed that thermostat in several seasons, and it's cheap and easy to do, so no harm in trying. But I'm not hopeful that will solve the issue.
 
Tell tale should be more or less the same temperature as the cooling water going in, much cooler than the water exiting the prop. once up to operating temperatures
 
What if your fuel pressure regulator is not working properly? This is just a guess so take it for what it’s worth, if your fuel pressure regulator is delivering more than 36psi to the injectors where’s the excess fuel going? One would think out the exhaust but is it possible that the excess fuel seep down thru the rings?

Would excess fuel cause the engine to run rich? If so check the spark plugs for fouling?

I’m not well versed in the fuel system so I may be way out in left field
 
Back
Top