95 Speedster twin 657X port engine trouble.

[Matt Garofalo]

Boat ran fine in the morning and then it was anchored for about 3 hours. Fired it up and the port engine idles fine but when I give it gas it bogs all the way until about 4000 rpms then rips wide open. Have to keep it at full throttle if I want to get past 4000 then it acts semi ok if I hold it wide open. Read a lot about fuel concerns so I went through the fuel filter (clean) the fuel selector (clean) the carb screens (clean) and all the fuel lines are newer. Made sure I had a good seal on the fuel filter o-ring and all the hose clamps. 145 PSI both cylinders, good spark on both cylinders. Noticed my wear ring had a chunk out of it on the port pump so I changed it out with no luck. I'm going to switch carbs from good engine to eliminate carb concerns but figured I would pick your brains and see if this is a common issue. I'm about to sink this POS!!!!

 

[USAF_Pride]

Did you try new plugs? Sometimes they spark outside the cylinder, but are weak under compression.

Question for the experts, would a sticking rave valve cause this?

 

[LouDoo]

Moving this thread to the 2-stroke sport boat section.

Lou

 

[Matt Garofalo]

Yes... has four new plugs and I switched the two from the good working engine over to the port side to eliminated faulty plugs.

 

[FinnExplorer]

There are no rave valves in 657x? Might still be something wrong with the carbs if you haven't changed them from the working engine.