300/440/550 Invisible weeds. Umm... what?

[Serio]

Ok so I have this weird problem. My ski runs perfectly engine wise; but, it runs exactly like it is full of weeds. Some back story: A friend and I were riding (pretty hard) and we decided to switch skis. After a little while some water got in my tank and we came back and fixed it. When we got back out it idled fine, but when you hit the throttle it just revs to the moon and doesn't go nearly as fast as it should (5-10 mph). There are NO weeds; even though, that is exactly what it feels like. I took the intake grate and ride plate off, and can see the (presumable stock) impeller. Slightly pitted and chipped but no major damage. When you turn the impeller by hand, it turns the drive shaft, and vise versa. If I hold the drive shaft, by putting a screwdriver in the hole behind the impeller, I can not turn the impeller by hand. The coupler seems fine, no gaps, good condition rubber. Any ideas as what to check first? Right now I see two options: Pull the entire pump and rip it apart so that I can check everything; or, pull the engine, and check the coupler connection. 1985 550. Aftermarket intake grate, and ride plate.

 

[FlightPlanDan]

Just a guess....wasted ware ring? It's an old ski. Nothing lasts forever. Check the pump. Use a flashlight to see the outer diameter of the impeller against the ware ring.

 

[Serio]

Thanks Dan, but nope. Just went out and checked, real small gap, I'd be worried if it was much tighter. Any other ideas? It was sudden too, like within an hour or so, which leads me to think something broke not slowly wore out. But maybe, idk! thanks for the help I just want to get this fixed so I can get back out on the water!

 

[augustaf]

Back in the day, I caught something in my pump locking it up. My "powerful" engine spun the coupler on the shaft - stripped the threads - and that was not readily evident turning the drive train by hand. Was not even going very fast.

 

[Serio]

So Augustaf, you think something got stuck, my engine stripped the threads, and so I should pull the engine and check it from that side? (just getting it clear thank you for the info) This is exactly what I'm looking for.

Also! What part would need replacing then? the driveshaft, coupler, crankshaftt, or all three? (please say one of the first two!)

 

[augustaf]

Maybe stick a piece of wood in the impeller and see if you can turn the engine manually by the flywheel (take of frnt. cover). If that is solid, the problem would have to be in the pump.
I had a short shaft (where the impeller is) break on a 750SX once -similar design. look at the parts breakdown on the web, i.e. http://216.37.204.203/Kawasaki_OEM/KawasakiPWC.asp?Type=13&A=14&B=14

 

[Serio]

Ok Thank you! I cant right now as it is late here, but I will tomorrow. Thank you! Now at least I have a starting point.

 

[special fx]

If you siliconed the ride plate to seal the edges.......don't! It will cause same behavior

 

[Serio]

O really? thanks special fx because it was like that when I bought it, so when I put it back together I won't re-seal

 

[Serio]

Ok, I took the flywheel cover off, blocked the impeller with some wood, and I could not turn the flywheel at all. I would take the pump off, except I need an 8 inch 8mm hex wrench and I can not find one anywhere!

 

[augustaf]

maybe you can locate a US size 5/16" allen wrench or socket, it's only a few thousands smaller and should work nicely.

 

[Tyler Zane]

O really? thanks special fx because it was like that when I bought it, so when I put it back together I won't re-seal

so was mine when i bought it. im not sure why people feel the need to seal the ride plate.

 

[Serio]

Thanks everyone for your help. After taking off the ride plate, intake grate, and checking the coupler, driveshaft, and impeller and nothing was wrong I decided to put it back together. On saturday I tried it just to see if it worked, and it did! The only thing I changed was that I removed the silicon sealent around the ride plate, and intake grate. I did notice though that now when I jump out of the water my rev limiter takes over, which it didnt before, kinda odd but no big deal. Thanks guys for your help!