Ocasional RPM loss

[oldcobia]

Have twin 2001 250 2 strokes. Ran great last year but sat for about 4 months. New gas put in tanks. Starboard ran great. Port also did great for about 30 miles at 4200 RPM. Then got occasional RPM loss in port engine too around 3200 RPM for a few minutes then would go back to 4200. This happened about 5 times in 15 miles. Back at dock all gas drained from filters were spotless and have been for the last year. Filters only have about 150 gallons through them. Is it sill possible that the VST filter could have a restriction?

[TownsendsFJR1300]

There's a drain screw and hose on the bottom of the VST. Put a clean catch can under the hose and drain. (I use a clean tuna fish can).

See if any crap/water comes out. You can also blow back into the hose to loosen and / or get more crap out if you see some. Squeezing the primer valve should help flush it as well..

What RPM does the engine run at @WOT? If your not getting your full RPM (5,000-5,500 RPM's), that would also point towards a fuel issue.

Does the VST filter also have 150 hours on it?

[oldcobia]

The first things I did when got back home was to drain the filters and VST tank. The fuel was pristine. Not a speck of debris or water. I never tried to get to WOT. Highest was 4700. I do not know when VST filter was changed. I think I am going to change all filters and clean the VST and replace that filter and go from there. Can't hurt. Thanks for all responses. Don

[TownsendsFJR1300]

Just a side note, it has been posted here that you can spray carb cleaner in thru the VST drain and it'll spray the filter (you spoke of and a PIA to access).

I asked about the WOT, as IF the VST was clogged, you likely would NOT get full throttle as the fuel would be limited...

Please post back what you find, the fix, etc... Thanks

[DennisG01]

I have a very similar thing happening, and has been for a few years now. I've yet to find the culprit. But here is my thread - with lot's of people offering advice and things to check. Maybe something in there will help you. http://www.yamahaoutboardparts.com/f...m-th23920.html