'98 Challenger 1800 - right engine won't rev past 4500

[Cody T]

Passenger engine is doing great and driver side behaves normally out of the water, but once it's in the water it has issues. Acceleration is slow and sporadic, and once it hits 4500 RPM it will not go over. Sounds normal at 4500 and at idle, and more throttle has no effect whatsoever.

I've replaced the impeller assembly, rebuilt the carbs and meticulously synchronized pop off pressures (both at exactly 34PSI), and pulled and cleaned both RAVEs, ensuring the bellows were adequately seated.

I'm running out of ideas, anybody have any suggestions?

 

[rusty nail]

do you have it in "forward". there is a rev limiter in the neutral position. if not that....could be starving for fuel. check filter, fuel selector switch, You can bypass all this with an external temporary tank directly to the carbs to eliminate all those possibilities.

 

[Cody T]

do you have it in "forward". there is a rev limiter in the neutral position. if not that....could be starving for fuel. check filter, fuel selector switch, You can bypass all this with an external temporary tank directly to the carbs to eliminate all those possibilities.

It was in forward. Neutral rev limit on both engines is around 3500 on mine. It will exceed 4500 easily in forward and out of the water but hits a wall at 4500 in the water and under load.

Fuel filter is brand new, it was replaced on both engines by the previous owner the day I picked up the boat about a month ago.

I'll check the selector switch today, only other thing I can think of as far as fuel would be the external fuel pump

 

[rusty nail]

i never trust someone else's work....i would probably still check the fuel filter. it could have sucked up the bottom of a bad tank. i am pretty sure they are also directional. pretty quick to set up a quick tank and bypass all that stuff to see if the problem is upstream from the carb.

 

[Cody T]

i never trust someone else's work....i would probably still check the fuel filter. it could have sucked up the bottom of a bad tank. i am pretty sure they are also directional. pretty quick to set up a quick tank and bypass all that stuff to see if the problem is upstream from the carb.

Very good point, especially considering I had to replace the entire jet pump assembly after the same man "rebuilt" it. I'll make sure the filter is still good and oriented correctly, and give the bypass a shot.

 

[Cody T]

Update: filter was oriented properly and there is no fuel valve on my challenger. I removed the external fuel pump and blew into the feed line, bubbles in tank with little resistance so flow should be good. Took the fuel pump apart and the engine pulse chamber had a lot of soot and corrosion, and it didn't look like the gasket was sealing properly any more. Got a new pump installed and will give it a shot out of the water this weekend

 

[Cody T]

Update 2: Ran for a short period out of the water after fuel pump replacement. Idle is healthy at 2500-3000 RPM, throttle is very responsive and doesn't tend to bog down anymore (RPMs previously dipped for a fraction of a second when throttled), and engine sounds like it runs much smoother, no more intermittent "coughing".

It seems promising but I won't know for sure until it's pushing water

 

[rusty nail]

fingers crossed.