DF 150 routine oil change, smells like gasoline

[Jaybord]

Doing my routine oil change on my 2019 DF150. I do it once a year. As it was draining it seemed as though it had a fuel smell to it. It wasn’t as dirty (black) in color as it has been in past changes but that’s probably because I didn’t run it much last year. Had new plugs put in back in October, and it’s been running great the past month as I’ve been able to get it out on the water. No fuel smell when running, no smoke, no leaks, etc.

Should I be concerned?

[Jaybord]

I have not made any long runs with the boat for a while. The locations I have been fishing are pretty close to the new ramp I’ve been using since my last oil change. Less than a mile, using the trolling motor most of the time.

[Murray]

I have the same problem with my 2009 DF90A, was told on here that the fuel can come from two places. Ruptured fuel pump gasket or too much fuel entering the VST and the excess fuel is pushed out the vent line which is connected to the crankcase. I had to pull the plastic flywheel cover off to see my vent line and was able to trace it to it's termination, my vent line does vent to atmosphere not the crankcase. Haven’t checked the fuel pump yet. I live on a small lake and most of my running is low idle. When the grandkids are visiting and pulling them on tubes and water skis then the fuel in oil is way less than idling around the lake.

[Jaybord]

I do a lot of idling, trolling too. Just not making the long 5+ mile runs that I used to do. I also looked at my service notes, the last oil change I did was almost 2 years ago. I was out of commission for over 6 months due to illness and failed to do my yearly fluid change. That plus the lack of long runs since that time is probably the culprit. I googled the issue, it actually has a term for it called “making oil” where the fuel going into the crankcase causes the oil level to rise. Hence “making oil”.

[Jaybord]

The Suzuki dealer who did my plug change back in October tested the the fuel pump and all was well.

[Murray]

If you’re confident that the fuel pump isn’t the culprit then that leaves the VST IF the vent line drains into the crankcase. Trace your vent line off the top of the VST before you start tearing into your VST.

[artdf175]

One of the main reasons that have been talked about on the forum about this issue has come down to the float valve in the VST.
If slightly out of adjustment or if some debris gets in, it may not close off completely. When that happens the excess fuel dumps off and where it goes depends on where the vent line terminates. Seems like most of the time it goes in the crank case and mixes with your oil.
This is not a difficult chore if you have some mechanical abilities, but highly suggest getting the official repair manual before tackling this.
Art

[Jaybord]

Where’s the VST located? What does it look like ?

[Murray]

Where’s the VST located? What does it look like ?

Behind the intake manifold. The screwdriver is touching the VST. From a 2009 DF90A, different engine than yours but I would suspect similar

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