Loss of thrust

[Double Trouble]

We took our '98 Sportster out for a little run started out had good power on both engines. Hit the beach for a bite & a couple adult beverages back on the water for some more riding. Everything seem to be going fine idled down to look around & check some of the sandbars out went to take back off & could not get back on plane. As I throttled up port engine would go to 4000rpms & starboard 7000rpms, but would not pick up or plane off had to idle back to ramp. My first thought was trash in the pumps, back on the trailer I inspected both jets & they both looked clear front & back. Both engines idle fine any ideas?
Thanks

 

[kustomkarl]

Check your spark plugs on the low rpm engine...one might be fouled. Correct spark plugs NGK BR8ES gapped to .021- .024" Check the throttle cable and see if it is in sync of the other engine. It might have too much play and not getting to full throttle. You might want to do a compression test. The compression should be ideally 150 psi. If all this checks out remove, the spark plugs and from the rear of the engine(PTO SIDE) see if you can turn the Jet Pump Shaft in a counter closkwise direction...you night have a bad bearing in the one jet pump causing too much friction and not getting high rpm's.

Karl

 

[timmyboy76]

carbs..

last time they were gonethru, and xcellerator checked for proper function.

 

[Chester]

It's a problem with the engine that was getting 7000 RPM, not the one that was at 4000 RPM. The starboard pump, at 7000 RPM, is cavitating. Did you try it again after you inspected the pumps? All it takes is a little bit of debris stuck in the impeller to lose all thrust and the mere act of pulling the boat out of the water can wash it out. Then upon inspection, it looks fine. If it still cavitates, remove that pump and have a closer inspection of the wear ring and impeller.

Chester