2006 DF150 OIl in Fuel

[dhacke]

One of my motors is having trouble starting and will not run. Recently replace the IAC valve. While going through the motor I opened the screw on top of the fuel rail to check fuel pump. when you turn the key on to prime the system, a mixture of fuel and oil sprays out the top. checked the oil in the crank case no smell of fuel not even on the dipstick. oil level is slightly lower but still normal. what can be causing the oil to get into the fuel?

[Harper]

No conclusions yet to this same problem. https://www.suzukioutboardforum.com/...sure-fuel-pump

[dhacke]

Harper thanks for the link.
after reading that post and the fuel concerns. my motor is on a world cat so i have 2 df150 on separate tanks. fuel was bought at the same place for both tanks. starboard motor runs perfect. port motor has the oil issue.

[redlowrey]

I am waiting for a reply from another post to see if there was oil in the evap line that comes off the top of the vst. I could not imagine oil getting past the seal in the low pressure pump without fuel getting past the diaphragm into the motor.

[catacom225]

Without going to any great expense, swap over the low pressure pumps, but in my opinion theirs more chance of fuel in the oil than oil in the fuel

[dhacke]

Spent a couple hours last night going through the fuel system. Checked fuel water separator as this filter is closes to tank to make sure no fowl play was done, filter was clean. Next went to the low pressure filter, filter also clean.

Continued to the vst where i drained it into a jar, fuel was extremely dirty and dark. Jar on the right. Will check jar after work to see if there was any separation.
Oil New.jpg
Jar on the right was the first 2 cycles of fuel that we pulled from the vst tank. we continued to pump the ball and turn key on and off to use fuel pump to flush the system until we got clean fuel flowing through the tank. this took about 7-8 times of fully draining the tank to get clear fuel. drained fuel rail to get gunk out of it. now that we had clear fuel cleaned the spark plugs off as they were very wet. it was late so was unable to just get new ones. Also put a bottle of Dry gas or Heat in the tank.

re primed the entire system, crank motored, took a couple of tries but finally started. motor ran rough for about 5 minutes and a little bit of smoke finally cleared up. turned motor off rechecked fuel. it still appeared to be clean. Took boat out for ride ran through all RPM's just fine. was about a 30 minute ride. Came home rechecked fuel still clean.

What could have caused this? fuel was filled from 2 different sides of the station as the pump hoses could reach across boat. tanks on boat are showing about half which is about 50 gallons in each.
maybe it wasn't oil but when it sprayed out of fuel rail onto boat it was really thick and acted like oil when washing off.

[Harper]

Other thing that puzzles me .... I'm not sure I'd see oil in the fuel on my motor. My oil is never dark to start with. Stays the same g-o-l-d (stupid website exed out the word g-o-l-d) color through to the next oil change.

Is it possible that ethanol is eating away at your fuel lines? Wrong kind of fuel hose can be a real problem. If after 12-14 years, the fuel hoses have been recently replaced, I'd sure be considering that possibility. You didn't mention ethanol, but the person in the other thread implied the use of ethanol laced gas when talking about phase separation.

Or possibly an old fuel line that is starting to fail. One thing you and the other person with the same problem seem to find, is that when you have cleaned everything out, you can get it running. But perhaps after sitting for a while, even just overnight, enough deteriorated fuel hose has accumulated that it all flows to the VST at once. Other person mentioned "residual solids" in the bottom of the sample jar.