97 gsxl pump cavitation

[rrider198]

I have a 1997 prod gsx ltd 130 hp 951 motor.
The boat flies on top end aprox 68 mph, but the boat revs up comming out of the hole like the pump is cavitating. Checked impeller and wear ring and it looks pretty good. When I talked to a SeaDoo dealer service guy he said that this is normal for that model boat. He said that it has a 140 mm pump and the cure was a 155 mm large hub pump on later models. He also said there is nothing I can do to remedy this problem. Does anyone have any info on this or some possible improvements. Thanks for any help you can give.

[Bryan Glynn]

That is normal for that particular model. That year had a steeper prop for better top speed (63-64, not 68 like your dream-o-meter says), but does cavitate out of the hole - it's desined that way.

There may be a better pitch or better prop/pump combo to run, I don't know.

[Bill O'Neal]

It doesn't have to be that way. Sea Doo did not use a rubber seal to mate the edge of the wear ring to the pump support plate on that model, and it causes a bit of cavatation out of the gate. A large bead of silicone on the pump support plate pump seal surface before installing the pump will seal it up. You must let it setup for at least 24 hours before riding the boat.
BTW, there was a 1997.5 "grey top" 951 powered SD GSX Limited that officially is designated as a 1998 model.
All 951 powered SD watercraft have 155mm pumps, not 140mm. All 787 and smaller motors use the 140mm pump.

The 1997.5 pump was aluminum/brass.
The 1998 pumps were plastic/brass with no outer rubber seal, and are too weak and known to crack the pump housing.
The 1999-2000 pumps were plastic /brass with an outer rubber seal and stronger reinforced housings. ( the best 951 pumps,IMO).
2001 and later pumps are all plastic, and work well in salt water, and adequet enough for rec riding. They use a rubber seal too.

Note: to swap to a pump that uses the rubber seal you must install the later model pump support plate, as the diameter of the sealing surface is larger for the rubber seal to fit into the support plate correctly, or you can cut the rubber seal with a razor knife to fit it into an earlier pump support plate, but it is kind of tricky to do it, so buy two seals at a time. longer studs are necessary to go from an all aluminum pump housing to a plastic pump housing, as plastic pumps have thicker mounting flanges.