One engine surging, other engine revving high

[casims2000]

I took my boat out yesterday for the first time this summer. Both engines started right up, but when I took off, the port engine started surging and the starboard engine was revving all the way at 8 rpm and I had it a little over half throttle.

Any ideas? I haven't changed the spark plugs since winterizing it. Would this cause the surging issue? Not sure about the high rev.

 

[pwgsx]

Wear rings could be shot .......

 

[Chakane]

Or it could be damaged impellers.

 

[devonte007]

Sounds to me like 2 different issues...

The surging engine: Could be something simple like spark plugs or bad/old gas. If you have not done so already as your spring prep, change the plugs and make sure you have fresh gas. See if that helps the surging engine.

The engine that is revving but not hooking up sounds like a propulsion issue and cavitation. It could be a bad wear ring, dinged up impeller, carbon seal, or maybe you sucked something up in there and it is stuck. You need to take it out of the water and carefully inspect the jet pump for any foreign objects and the clearance between the wear ring and impeller. Also check to see if the impeller looks good, all the blades straight with no dings or any damage. If possible take some close up pics and post them here, we can help you diagnose.

Report back and let us know what you find...