Surging when trimming up

[skeems]

I have a Yamaha 90 and while coming back from fishing today it got on plane ok but when I went to trim up the motor the engine started reving up and down or surging. My prop is aluminum and is worn on the leading edge in some places. I filed all the nicks off last night. THis morning everything was fine but then the water was like glass. The leading edge is almost "sharp". It is the same prop that came w/ the motor. And the motor has 130 hrs on it. I think I need a new prop and trim tabs.

 

[rodbolt]

Re: Surging when trimming up

a model number may help.

 

[DJ]

Re: Surging when trimming up

Got tach?

You may be up against the rev limiter.

 

[JUSTINTIME]

Re: Surging when trimming up

sounds like u were over trimmed

 

[skeems]

Re: Surging when trimming up

Model # It is a 2002 Yamaha Outboard motor??? It is running at 4400 rpm's and it is running 30 knots. HAd the prop re-worked. Engine surge is still there. I trim just a tad andit still surge.

 

[rodbolt]

Re: Surging when trimming up

as I still dont see a model number I still cannot advise.
sorry.
may have actually been more than one model of the 90 hp in 02 with possibly more than 1 ign system. generally what your describing is dirty or loose connections between the battery and the ecu.
the sudden current draw is dumping system voltage.
from there depending on which ign system its running it can do funny things. normaly the ECU will revert to default until it sees 12V again.