Fast boat in good condition?

[whitewheels]

Can one say that condition of carbonseal,wearring and impeller reflects the top speed and vice versa? Offcourse with a good running engine
For example.
My sportster le does 44-45mph on a garmin gps.
If I pin it from stand still it cavitates a little(witch I read is normal?) and then is pretty fast off the hole,not like a twin engine but fairly quick.
The thing is that the impeller got some scuffmarks,wearring got some wear and the boot for the carbon seal have I adjusted with homemade shims.
I 'm thinking of a pump rebuild til next season but if it does 45mph maybe I can put my money on something else for a season or two?

 

[whitewheels]

.....just want to learn. No other reason. This is my first hole season with jet driven watercraft

 

[Coastiejoe]

To some degree, yes..

When under substantial load such as from a stand still or a heavy turn, any imperfections can/will translate into a lesser performance.. Once the ski/boat does get to speed, the imperfections (as long as they are minor) will affect performance minimally at best. Officially, the top end speed would be decreased, but we are talking a nearly immeasurable figure relative to the norm of the boat/ski.

If the impeller is bad such as being bent and or the CS is sucking air bad, then yes, the top end will also be affected.

 

[whitewheels]

Actually I have another reason asking. I've subscribe to Andy4k6 restoration post and that's were I got intressted in this with seals,pumps etc
Anyway I got great topspeed and out of the hole preformance but in the middel not so good. The revs fluxuates like 500rpm from 4500-7200rpm except around fast crusinspeed 6000rpm.
First I thought it could be a very worn throttlecable but the symtoms from that doesn't add up so I got into impeller and wearrings.
Maybe then the wear on the wearring and scuff marks on impeller does effect performance at thoose rpm

 

[Andy4k6]

Thanks for following my thread I didn't think anyone was

I wouldn't expect wear rings impellers or carbon seals to cause a fluctuation while maintaining a constant speed, I would expect that to be fuel or engine related tbh.

I assume you don't have any misfires etc?

Andy

 

[whitewheels]

No missfire. I do have a fuelselector that need to be replaced....maybe it's not open up fully. Know I can't get it in reserv.
I rule out a worn sticky throttle cable because while idle at dock in neutral ,I can rev it and the rev drop right when I pull it back to idle...like braap braap

 

[whitewheels]

While on the subject cs,impeller etc
I hear talk about bearing seal insted of carbonring seal. How does that work?
Also I read about different impellers pitch etc. This must be a jungle to sort out or does ,manufacures(like solar) have info/charts what impeller does what in different boats and with differnt engines?

 

[whitewheels]

...yeah,I'm really new to this
Here in sweden the small jetboat scene is almost non excisting.
The pwc market has really take of like a rocket 2-3 years ago but it's still very few that wrench with their mashines