Sudden lack of thrust

[zibius]

Hi, with ROTAX 250 HP on a Chapparal. Its weird that everything is fine, acceleration ok, going on plane. But then i would slow down, and when I want to start up again, RPM ok but no thrust. Impeller is ok, wear ring is not to bad, no big damage. Changed the spark plugs and tubes. What else could I check before sending it to a garage? Thanks

 

[anmut]

I'm not familiar with those boats as much as a Yamaha, but almost sounds like your gate could be stuck down?

 

[Burny1250]

Hi, with ROTAX 250 HP on a Chapparal. Its weird that everything is fine, acceleration ok, going on plane. But then i would slow down, and when I want to start up again, RPM ok but no thrust. Impeller is ok, wear ring is not to bad, no big damage. Changed the spark plugs and tubes. What else could I check before sending it to a garage? Thanks

I'm having a similar issue. Past 6000 - 6500 RPM it is not accelerating and with more than a couple people on board it has difficulty getting onto plane. Once on plane it will accelerate over 6500 RPM but only if throttle is increased gradually.

Hitting full throttle after getting onto plane it will bounce off the rev limiter and will not accelerate like it normally would.

 

[zibius]

I'm having a similar issue. Past 6000 - 6500 RPM it is not accelerating and with more than a couple people on board it has difficulty getting onto plane. Once on plane it will accelerate over 6500 RPM but only if throttle is increased gradually.

Hitting full throttle after getting onto plane it will bounce off the rev limiter and will not accelerate like it normally would.

Someobdy from a facebook group mentionned the same sympthom. Even worst, it was sometime ok, sometime not so much. He neded up changing the wear ring and it fixed the problem.