98 speedster port engine wont go past 5600 rpms

[cenzo4dub]

hi im new to this forum and i recently purchased this 98 speedster which is my first boat of any kind never owned a jetski either. i took it out for a test ride last week to see how everything worked incase it needed any work before the season started. so i started up good hit the open water and it wouldnt take off kinda just revved high and didnt move. the boat had 4 people on it. the port side engine also kept stalling and was shaking on me i fifgured maybe it was a spark plug issue sisnce it was the first time running since it was winterized from the previous owner. i also thought maybe something was stuck in the intake grill. i pulled on the weedless lever and it didnt come out that far (first time using it so i wasnt sure how far it was suppossed to come out) went back to the dock and while my friend got me a tool out of his car for the spark plug i pulled on the lever again and i pulled harder and it came out alot farther (the right amount) before he got back i started it back up and it seemed to run smoother(not shaking as much) i also changed the spark plugs and it seemed ok. so we took it back out and it wasnt stalling or anything got it up to a lil over 40 mph in the choppy water starboard engine got about 7000 rpms and port side only 5600. since then i pulled the rave valves out and cleaned them they didnt look too bad as the previous owner said he had recentcly cleaned them. wondering what else to check out. im thinking maybe its a carb issue. also i checked the compression on all four cylinders and they all had 90 psi which is weird bc everyone saying it should have around 140 but doesnt make sense since my one engine ran very strong and smooth no problems but the other one not past 5600. nothing visually in the engine bay looks like its leaking or anything. thanks in advance for any help or suggestions

 

[Dr Honda]

Well... you found your prob. If they engines are showing 90 psi... they are about ready to die. A fresh 800 engine should be showing 145 to 150 psi. at 90 psi, I'm surprised it's running at all. Just to make sure, verify that your gauge is OK. (Hook it to an air compressor with a known good gauge)

Now... the revving up and not going anywhere, is cavitation. You could have a leak around the pump, the carbon ring, or your wear ring is out of spec. BUT... normally very bad cavitation is from the carbon ring. (The pump sucks air past it, and you don't go anywhere)

 

[RFoster130]

For all 4 cylinders to show 90, with 1 engine running good,makes me think you have a bad gauge or you are doing something wrong. Double check the compression numbers.

Like Doc said, you sound like you have a cavitation issue. The boat will handle much different if you fix that. As far as it not hitting max rpm, i would check all stuff fuel and spark related.

 

[RFoster130]

Also, I know it is a little late now, but this is the exact reason I always tell people I would never buy a boat without a water test. Way too many problems that you might not notice unless you take it out. Too bad you didn't find us before you bough itt, might have saved a few bucks...Anyway, you are here now and hopefully we can help you get straightened out. Welcome!!!

 

[howie099]

Make sure your compression tester has a check valve in it. A cheap tester from like HarbFreight for $20 doesn't have the check valve in it and it will always show low. I know I tried both to prove it. A good engine tester from like MotionPro cost $150 and other good companies have the check valve in it. I highly doubt all 4 cylinder have 90 PSI. You would have no power, starting would suck, and you would be smoking bad from the exhaust.

 

[cenzo4dub]

ok well today i had my carbs apart at and one of the filters was pretty dirty and i cleaned everything else out hopefully that was my rpm issue. and just to put it out there i do have one of those cheap harbor freight testers. i will try and borrow one from this guy at work tommorow and get a better reading tommorow hopefully that number changes. the impeller is in realy good shape and no dings or anything i will also check the clearance of the wear ring tommorow also. how would i check the carbon ring. but i def had alot of power started pretty good and it smoked a lil bit when i first started it but i figured it was from being fogged after running it for a bit there was much smoke at all if any. about the water test i talked to the guy a few times and he offered to water test it on a sunday but i had the bug and wanted to buy something and wound up having a day off on a wednesday and went up and picked it up. he told me a few times he would water test it for me if i came back on sunday which i didnt want to do bc it was 2 1/2 hours away. i also had the fuel gauge issue but i took out the sender and took out the fuse and put some solder in place so thats all good. it wasnt cavitating too bad, more when the one engine kept stalling once i got it straightened out it was slightly. i will check the clearances tommorow. the one good thing about this all is i work at a mechanic shop im not an "A" mechanic but i have plenty of tools to fix it and will be taking care of everything my self so i can save a few bucks. i plan on changing the jet pump oil anyway so if i need to do the wear rings i can bang it all out at once.

 

[BMANN06]

I would also go through and clean your exhaust rave valves, when I first bought my 98 speedster I had some funky rpm issues too. After cleaning them up I saw a signifigant improvement in reaching max rpms.