2000 Challenger 717 engines RPM problem

[arawnsd]

Hello,

I recently bought a 2000 Challenger, and the compression tests checked out ok.

The first time I got the boat out on the lake (couldn't do that when I bought it, it was still too early in the year), the right engine wouldn't go much above 4000 rpm after running the boat for about 30 minutes.

Playing with the throttle, I could get it to jump up to 6000 or so, but it would quickly fade back to 4000 rpm and hang steady at that point, regardless if the throttle was pushed forward.

The gas was mostly new (there were a couple gallons in it when I got it, but I filled it with new gas).

The engine did not sound like it was having any difficulty, as it was making the exact same noise as the left engine when at the same rpm.

I've googled and saw a bunch of RAVE valve mentions, but that's on a 787 engine, my 717 engines don't have a rave valve. (Pity, the problem I'm having seems like a common and easy fix (clean the rave valve) on the 787.)

Thank you in advance for any suggestions you can give.

 

[Dr Honda]

The carb(s) need cleaned.


Also... you said the compression was good. what was it, and how did you do the test? It's probably fine... but I like to have the actual number.


Lastly... did you try to "pop" the choke at all? If you have a fueling issue... if you pop the choke, closed, and open... and the RPM's climb... then it's 100% a carb issue.

 

[arawnsd]

Thanks Tony.

The compression test results for the engine all came back in the high 140's. I tested each cylinder a couple times, and the results were always just a smidge under 150psi. As for the procedure, I did a bunch of googling to find out how to do it (removed spark plugs, screwed in gauge, started, let it run a few seconds) and followed the steps. It was pretty easy.

I'm no gear head, but I do have the shop manual, is cleaning the carbs something a novice should even attempt if I've got the patience? I'm not an idiot, but my time is usually spent in the wood shop, not the garage...

I did not try to pop the choke, but now I wish I did... (The water is a 40 minute drive from me, so it's not a quick thing to try out.)