1996 GTX - Very minor cavitation on hard acceleration

[Lothsahn]

When I floor my 1996 GTX from a stop it briefly (.5 seconds) revs to 7000 rpm, then falls to 6200 RPM as it accelerates, rising back as it picks up speed. If I have more weight on the seadoo it stays at 7000 rpm longer.

Can't really test max speed due to speed limits on the lake but it hits at least 54mph.

Just redid both carbs, replaced the impeller with a Solas SD-CD 15/23. Installed a new neoprene seal and wear ring which fit with perfect clearance around the impeller. Replaced the carbon ring and bellows with new clip.

Is it normal to rev like that and then fall down? If not, what could it be?

 

[artr]

I had a similar problem and replaced the hat, carbon ring and bellows and that resolved it. You did not mention replacing the hat. When I inspected mine there was some areas that appeared darker. I posted a picture under "carbon ring inspection and replacement". Miki called it out as pitting of the surface. The surface of the hat felt smooth to the touch but under magnification those dark areas were deterioration of the surface. Any air leak into the jet pump causes cavitation. Under hard acceleration there is a tremendous vacuum caused by the jet pump. Also if the ride plate is not properly sealed to the hull, the same air leaks can occur.

 

[Lothsahn]

Thank you artr. I will try this.

So yours does not rev immediately to 7000 on a start from stopped?

 

[artr]

It might for about a second but it is hardly noticeable now. It used to be like a slipping clutch until you backed off the throttle. I do not have a perfect impeller or new wear ring so it might be that now. It is 100% better now than it was.