what size of prop shopuld i be running?

[snoopy]

guys got ski going finally after winter project. use to turn a 14/20 skat. after all mods this winter i put in a 15/21.well sitting on idle and hitting the throttle hard she spins pretty badly out of the gate.mods i done over the winter was the 3 degree keyway ferchos vf3 reeds trued the hull ported crankcases and polished exhaust ports and exhaust manifold. the mid range really hits hard and if you go easy on the throttle is ok out of hole but when you hit hard it just spins. the pump is well sealed. any ideas anyone?

[flyboy]

1200 grate? I dont see you turning a DF 15 that hard out of the hole

[snoopy]

yea 1200 grate matched to pump shoe. last year the 14/20 was perfect. also i havent put on the rubber nose boot on this prop

[flyboy]

the boot shouldn't matter. I just can't imagine you spinning a 15/21 that hard out of the hole..

how much do you weigh?

[great lakes gpr 1200]

1200 grate? I dont see you turning a DF 15 that hard out of the hole

what exit cone (on pump) do you have? 87 or 85? with a 85 mine spins a little worst out of the hole.

But I am with Flyboy,, check your pump,, a 15 on the bottom should be more than enough with your mods..make sure you grate is tight, and pump is sealed...

[porksword]

What year ski? New style pump or old style?
Check to make sure you dont have any weeds or trash in the tunnel or wraped around the prop.

[Duke]

guys got ski going finally after winter project. use to turn a 14/20 skat. after all mods this winter i put in a 15/21.well sitting on idle and hitting the throttle hard she spins pretty badly out of the gate.mods i done over the winter was the 3 degree keyway ferchos vf3 reeds trued the hull ported crankcases and polished exhaust ports and exhaust manifold. the mid range really hits hard and if you go easy on the throttle is ok out of hole but when you hit hard it just spins. the pump is well sealed. any ideas anyone?

Is the 15-21 new? Check your prop to liner clearence before you do anything drastic. Ideal is 8-12 thousandths. A wore out prop will not come out of the hole no matter what pitch.

[snoopy]

its a 3 degree xlt nozle. everything is tight and well sealed. the prop is a borrowed prop from a fella who got it from fercho. he says ther is only about 20 hours on it. i will check the clearance tonite. only weigh 11 stone.
its a 04 13.these are only mods done this winter on top of what i had pervious winter.

[VOODOO]

We also need to know what rpm's you're turning at WOT.

[snoopy]

was out last night finished of running in the new pisitions. half tank of fuel and ski still cavitates of the bottom. once the fuel levels went down to near empty it stopped. hope to this weekend to get the efi dialled in and find out what revs im hitting. why would it stop caviating with low fuel?

thanks

carl