300/440/550 Need More Help!

[SkiPro]

Hey guys, I posted a thread awhile back about my 91 550sx. It would start and run fine out of the water. Then when i put it in the water it will run ok for about 2 minutes. Then start to get boggey, Then it gets so bad it wont even get on a plain And it will be wide open bearlley moving. So slow i can bearley get it back to shore. So i replaced the plugs, Drained the gas and tryed to adjust the carb. Nothing worked. Then i searched for and exhaust leak, Didn't find one. I then took it to the lake and rode it till it did its thing. Hopped off took the hood off, put it back on and it did the same thing. Except wouldn't even run for that short period of time. So theres no exhaust leak. I finally got frustrated and took it to a local shop. I waited four weeks for them to replace the the diaphram on the carb, the one closest to the fuel pump. They also replaced the pickup line in the tank. So i Got it back took it to the lake, It did the exact same thing as it did before i took it to them, except for it ran worse in that short span of time. Took it back to them and took the guy to the lake to show him. He adjusted the carb a little and it ran better, Then it crapped out like ussual. He gave me my money back and told me not to bring it back because he doesn't work on kawasaki's. So i know its not the carb, or an exhaust leak, or the plugs or gas, or any water getting into the fuel bowl thingy. I'm just stumped and Don't know what it could be. Could it be a reed or something? i have no clue and way bummed, Does anybody have any ideas? Thanks!

 

[Kohldanielzimmer]

Have you performed a Compression check and leak down test?

 

[screaming440]

this could be a lot of things but don't exclude the carb yet cuz it does not sound like the guy rebuilt it. the needle and seat in these often leak and the carb kit does not come with a new one so it is likly it did not get replaced. also if he used a cheap carb kit like SBT the spring that holds the needle shut is not correct and the fuel pressure the neadle ones at (popoff pressure) will be off.

i would replace the plugs (ngk b7es or b8es, be sure to gap them to .28) run it till you have a problem then pull the plugs an see it the look normal, fuel wet or crusty white lean.


here is a list of some of the things that can cause you problem in no order.

1. crank seals
2. leaking neadle and seat
3. plug wires and caps
4. spark plugs and incorrect gap
5. ign coil
6. stator
7. fuel system air leak
8. pluged fuel filter or fuel line.
9. water in the water sep
10. exhaust leak
11. stop switch short
12. blocked exhaust (water box baffle, pinched hose)
13. fuel pump pulse line