Seeking help with 2000 Seadoo LRV

[Irondom]

Where to begin....

New to the board, greetings to all, really hoping to get some help. I bought a 2000 Seadoo LRV (68 hours on it) about a month ago. I once again put my faith in humanity and purchased it without sea trialing it, yes I know, my fault, and God do I feel stupid now.

I will try to sum this up quick and avoid putting you all to sleep. The first time I put the ski in the water it started right up, idled well, plained out good, but at full throttle started revving. Since then I have replaced all the fuel line, replaced the fuel selector switch, replaced the front bowl filter, rebuilt carbs (replaced small carb filters), pulled fuel tank stem out to make sure filter net on bottom was clean, and put new gas in ski.

Second time in the water, everything was the same, except full throttle held constant for 30 seconds then it dropped rpms and ran at half speed. As much as I played with the throttle, it kept dropping out at full throttle. I could find a sweet spot at 35mph where it would hold constant without dropping out. I pulled the carbs again and looked up carb specs, low speed adjustment =1 1/2 turns from seated, high speed adjustment =0 turns. What I found was low speed adjustment =1 1/2 turns from seated, high speed adjustment =1 1/2 turns from seated position. Finding the high speed adjustment at 1.5 out made me think that maybe the previous owner adjusted it to try and compensate for the old gray fuel lines and dirty filters, so I reset the high speed adjustment to 0 and tried again.

Third time in the water with carb adjustments at factory specs, the ski ran worse than ever. Startup, idle, and take off were good, but midrange to high throttle was all over the place, and no more sweet spot. I have since then pulled the carbs 6 times trying high speed settings from 0 to 1.50 turns, and nothing helps. To make matters worse, the last time I tested the ski, it displayed the symptoms of a worn wear ring. Hi RPM's, wouldn't go above 25 mph, and the impeller is free of any obstructions. I limped the ski back to the ramp and pulled it home. I am now making a last ditch effort to seek help before taking it to a certified ski mechanic. Any help would be greatly appreciated!

 

[Sportster-2001-951C-Stock]

Okay, so maybe your 951 was running correctly before you rebuilt the carburetors but there was a problem with the jet pump (engine revving but ski wasn't moving, indicates the impeller is cavitating and/or being airated).

Seems now there are two problems.

Low thrust - If the carbon driveshaft seal is damaged/worn/ineffective the jetpump will suck air from the bilge and the impeller will become airated (some call this cavitation). If the wear ring is chewed up the impeller will cavitate (not to be confused with airation but result is basically same).

You should at some point remove, disassemble and clean the RAVE valves if you haven't yet.

Cylinder compression test should be around 130psi, my worn but still running fine engine blows 122 psi

Fouled spark plugs will give 1/2 power and very low idle. So will a damaged cylinder that's got abnormally low compression.

Fuel system - Yes, 0-turns on HS mixture screws works fine. LS mix screws are for fine-tuning idle mixture, you're looking for no loadup and no lean stalls while idling, along with an easy warm restart after 15 minutes shutdown heat soak. Factory recommended LS setting works well for in-water idle of 1500~1600 RPM.

Hopefully when you installed the rebuilt carburetors, you didn't get one of the carb base gaskets out of position. This is an easy mistake to make. I guess the ski wouldn't idle well if this happened.

The metering springs in the carburetors should be the originals, too easy to install the incorrect ones if the kit included them they likely are incorrect unless you did your homework and verified the detail.

There's a good chance since you replaced the fuel lines, you made some plumbing mistakes. And you should confirm there are no air leaks by low pressure air testing. Remember to remove the fuel gas cap to avoid pressurizing the fuel tank with air and creating a hazardous condition or damaging the fuel tank. Air pressure of 5psi or less should be plenty sufficient for locating any leak points (such as fuel/water separator cup o-ring). Too much air pressure while testing can damage things so take precaution.

Grab an 12V electric or hand operated fuel pump and pump fuel from the fuel line connected at the carburetor's fuel pump, confirm fuel delivery is not being interrupted by some kind of issue. There should be almost no air bubbles (very few). Autoparts stores / ebay have el-cheapo 12V fuel pumps and I use these often to empty remaining fuel from tanks at end of season during winter storage preparation. Fresh fuel is imperative for 2-strokes and marine engines, stale fuel avoided.

Not sure what else, can continue tomorrow....