Sea doo Challanger 1800

[Ventil]

Hi,

something unusual started to happen with my speedboat yesterday,
the boat has two rotax engines (Jet fueled) 2T
The problem is with the first engine, when I press the gas pedal, after 5k rpm it automatically swiches to 8k rpm, but there is no power.
What could be the problem?

If someone coucd help me, that woud be great, thanks..

Kind regards

 

[Waterluvr]

Your motor is experiencing a common problem called cavitation, which is a void and interruption created in the pump discharge due to air flowing into the intake side of the jet pump. There are two common sources of this, the neoprene seal on the pump mount is known to be a problem and a worn carbon seal inside the boat on the driveshaft will allow air from the hull to enter the pump.

Your problem is likely in the carbon seal since it only happens at very high rpm's, pump removal is required to replace it and a new neoprene pump seal should be used any time that is off for servicing. A new bellows will ensure proper tension is applied to the seal and that should fix your problem.

You can get the shop service manual for your boat from this website, it is very helpful to read and have available when working on the boat, the procedure for replacing that is in the manual.

 

[Coastiejoe]

Could also be the wear ring. If the gap is greater than the width of a dime, replace it.

 

[howie099]

Yep to the 2 main things. Wear ring and Carbone seal. If you need the seal get the OEM one and the new style OEM boot. it applies more pressure on the seal. If you have do that put in a wear ring since it is all apart unless you just did one this season or so ago. Do it all right at once lets you spend more time on the water...