96 Challenger jet pump issue

[Minton33]

I just recently bought a Seadoo challenger at work that someone had traded in. I took it out and at full throttle it rev limiters, it won’t get up on a plane with 2 people on it and only went about 15. With just me on it finally got up on a plane after about 45 seconds and went just under 30. I though forsure it would need a wear ring or impeller.

I pulled the pump off and the impeller looks brand new( talked to the guy it came from and it was just replaced) and the wear ring is perfect except for the first half inch where the impeller doesn’t even touch being as the impeller is rounded off in the front.

I’m not sure what to do now. Looking for help or suggestions. I did notice there was no gasket on the front of the pump as well as pretty much no sealant

 

[etemplet]

If there is no neoprene gasket (I'm assuming it is 140mm pump) that could be your problem. Also not enough closing pressure on the water seal inside the hull. Good Luck !

 

[Minton33]

If there is no neoprene gasket (I'm assuming it is 140mm pump) that could be your problem. Also not enough closing pressure on the water seal inside the hull. Good Luck !

Yeah I suspected that. I’m going to go ahead and replace the wear ring since I have one and the pumps off. I feel like sealing the front of the pump will make as much difference as anything though. I’m hoping anyway now with the water seal inside the hull are you taking about the carbon seal? It doesn’t leak any water so I would assume it’s not drawing air but I could be totally wrong

 

[etemplet]

Yes the water seal inside the hull. I never had that problem previously but rode a ski recently and WOW !!! when it cavitates you know it. LOL

 

[Minton33]

Okay I replaced the wear ring and The seal between the pump annd hull and it helped significantly. It no longer rev limiters but it still cavitates terrible. It takes at least a minute if not longer to get on a plane. And everyone inside has to go to the front of the boat or it never will plane. It has a skat trak 14.5 - 22.5 impeller. I’m wondering if it’s not the correct pitch or just totally wrong for it. When sitting still you can only go to about half throttle and pretty much lose momentum when you go past it

 

[Minton33]

Yes the water seal inside the hull. I never had that problem previously but rode a ski recently and WOW !!! when it cavitates you know it. LOL

That was the issue. I really appreciate it. There was almost no pressure on the seal at all. I swapped clip positions on the driveshaft and loosened the bellow and slid it forward some and wow. Crazy how big a difference it makes. Takes right off now.

 

[etemplet]

That was the issue. I really appreciate it. There was almost no pressure on the seal at all. I swapped clip positions on the driveshaft and loosened the bellow and slid it forward some and wow. Crazy how big a difference it makes. Takes right off now.

I've seen large o-rings used as a spacer behind the bellows to put more pressure on the seal. Glad you're up and running !!