Fuel related problem?

[Sunstate78]

Hello everyone. New to the forum. I have an 07 DF 225 with about 310 hrs. Last Sunday I took the boat out fishing and noticed on the way out that occasionally the engine would rev up on its own without an increase in speed. When I throttled back down to neutral it seemed to correct itself and I then began to throttle up again.

After about 3 hrs or so fishing I started the engine to head home. After a few minutes when I got it up on plane, the motor stalled out. Couldn't get it started. I pumped the primer bulb (which was very soft) and the engine started right up and never stalled out again but noticed it was running a little rough.

Prior to all this, I had maintenance done in March where Hi & low pressure fuel filters were changed, water seperator filter changed. I also think the VST was checked (wouldnt they have to in order to get to the high pressure filter?).

I have been using the dreaded ethanol fuel in the engine with an additive called Gas Shok which is supposed to remove any water. I am having my tank draned tomorrow and all ethanol fuel will be gone.

Other than inspecting the fuel lines (which I will do today), does anybody have any other ideas as to what the problem might be?

Thx

[Seaduck]

On my 07 df115 the high pressure filter sits on top of the vst tank. So the filter can be removed without going into the vst. I think you are headed in the right direction. Cleaning and removing all lines, filters and bulbs. Ethanol gas can be awful for outboards. I went through the same thing. I also put a new pickup tube in my gas tank has well as new fittings. Took out the older anitsyphon fitting and replaced with one that didnt have it. Good luck with your motor.

[aquamort]

Are you sure there was an increase in revs but not speed? That would tell me there was likely cavitation? But yeah get rid of that ethanol crap. Im in Australia and only use premium (98Oct) in my DF140 which never misses a beat.