Question on Yamaha 90 2 Stroke

General Boats and Motors
1

Hopefully a simple question:

I have a 2002 Yamaha 2 stroke with oil injection. Has been running great.

Had it out Friday, glass smooth so I was trimming up to find the max trim angle then it ventillated.

I tried trimming down to re-grab the water, didn’t re-connect…then all of a sudden RPMs started dropping. Dropped back to below 2000 or so and would not throttle up until I manually pulled the throttle back to almost neutral then back forward.

Ran find the rest of the day through all RPM ranges without a single hiccup.

Does the rev-limiter kick in reduced RPM or “safe mode” when it revs to high or could I have another intermittant problem?

I had also just finished (well 20 minutes prior) decarbing the engine using sea foam.

Clean filters (racor and on-engine), plugs have about 12 hours on them. Good fuel.

Have a trip coming up in two weeks, want to make sure it is good before I haul it down the road.

Thanks.

2

the rev limiter will only cut out spark on select cylinders until RPM’S are reduced.

3

Thanks for the reply.

Maybe a fouled plug then from the decarb. I did the “Dunk” method running at low RPM for 15 minute spurts.

I’ll try running it again this weekend and see if there are any problems.

4

Mine has done the same thing a few times, always when it over-revved for whatever reason, either trimmed too high, or leaving the water when hitting a wake.

Blackwaterkatz

5

I have the same motor and had the same thing (or very similar thing) happen to me. I would not be concerned.

Kevin
1720 Sea Hunt w/ 90hp Yam
M’Ocean Sickness

6

sounds like the over rev protection to me

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