Spinning up/Cavitation on the line???

[grantuk]

I am a CC racer and have just finished my ski, I am getting lots of cavitation off the line when going from idle to WOT.

It hits the limiter at least 3 times before it hooks and by this time I am a boat length down on the holeshot. It has a new wear ring (stock) and 15/19 (non R), pump seal is good.

Any ideas?

[redflag]

how is the carbon seal if you still have one?????

[grantuk]

I still have one, its in fairly good condition. I have heard that the pressure of the pump when you hit WOT can pull the carbon ring back and draw air causing cavitation also, anyone heard this?

[Franko]

I still have one, its in fairly good condition. I have heard that the pressure of the pump when you hit WOT can pull the carbon ring back and draw air causing cavitation also, anyone heard this?

Yes, that is exactly what happens if the carbon ring is worn or damaged. Also, check your engine allignment. Make sure the pump support bolts on the inside of the hull are tight. Check the "shark teeth" in the pump tunnel to make sure none are damaged.

[grantuk]

I haven't got any sharks teeth any more
One of the les driveshaft seals may help?

I'm going to change the bearing in the pump first

[meeper]

i just put a zip tie in back of the carbon ring below putting more tension on the carbon ring this morning, i was starting to see a slight black mark inside the hull