Trim tabs for 95 Speedster

[gm-mastertech]

Hello, everyone. Quick question; I know most of you deal with only PWC's, however I try to work on everything especially the Speedster/Sportster jet boats. The particular model I am working on is a 95 Speedster with the twin 657X's. I have overhauled one of the engines. (I've done many of these in the regular PWC's) However, I was in the process of breaking it in and this boat will not plane off unless both engines are at 7,000 rpms!! I've seen some trim tabs advertised that are supposed to dramatically help it to plane. Has anyone had any experience with these? It is a customer's boat and I don't want to release it until I know the engine is properly broken in. Thanks everyone

[Bill O'Neal2]

Re: Trim tabs for 95 Speedster

Are you experencing cavatation upon accelleration?
If so, a pair of Skat Trak Swirl impellors will make a world of difference.

[gm-mastertech]

Re: Trim tabs for 95 Speedster

Thanks, Bill for the reply. Somewhat, but the main problem is that it thrusts so hard at first, it is basically lifting the grate out of water and sucking air. This allows both engines to hit the rev limiters like lightning. Even if passengers get to the front of the boat, it still lifts pretty hard. If you try to ease into the engines they will build to about 4,000 and start it again. I know this may be out of the ordinary, but if any of you administrators or seniors of this site have any questions on a GM product you may drive, I will be happy to give advise as well. I think it is very awesome the way you guys help everyone out in these forums. I am Master certified in everything General Motors. Thanks again

[dzuskin]

Re: Trim tabs for 95 Speedster

There is a forum devoted to Jetboats with a search option. A lot of discussion about trim tabs, etc.

www.jetboating.net

[Paulie]

Re: Trim tabs for 95 Speedster

Swirl imps will help, but bone stock that boat should hurt your neck. So,
you are sucking air some where causing cavitation. Carrier seals, pump seals,
pump obstruction, some thing in the drive line is causing your problem. Seek and you shall find. Then when right, you can decide if you want more, ie
swirl imp. Trim tabs for the 14.5 are more for bouncing than increased hole
shot. They will help that too, but usually these boats are so quick, it is not
the primary reason to intall. Good Luck !

[gm-mastertech]

Re: Trim tabs for 95 Speedster

Thanks guys for all the advice!!