Hollymax0428
New Member
I'm new to jet power & sorry about the length of the message but I need help to get this boat going properly.
Mainly my problem is knowing how far down I can screw the RAV valves without causing something damage & how to adjust the carbys.
1st time out with the boat 2 weeks ago it was very slow to plane with 1 person and for a breif period got to around 35 mph after quite a bit of time, but mostly 28-30 mph.
2 People in it was much worse and wouldn't plane doing around 25 mph, 3 people 20 mph.
Revs at 3/4 throttle was 5000 rpm and full throttle still 5,000 rpm.
I was told by the Jetski mechanic it might be the drive shaft carbon seal.
When I pulled the pump off I found there was around 45-50 thou clearance between the impeller and the wear ring.
what I have done so far is:
Replaced wear ring with a new one and put in a used standard impeller with straight blades, the one in there was a seadoo swirl impeller (which was apparently offered as better performance) but had worn around the outside edge.
Replaced the neoprene boot seal between pump housing and hull.
Checked the drive shaft carbon seal which was OK and new 'O' rings on the Seal Carrier.
2nd time out today still slow extremely slow to plane (around 200-300 yards) but with 2 people eventually got up to 30-32 mph, with 1 person slightly faster but still slow to plane. Revs at 3/4 throttle was still 5000 rpm and full throttle no better at 5,000 rpm.
What i found was if i turned hard right and crossed the wake i could get the revs up to the 7000 limiter and it was accelerating but as it started to grip revs dropped immediatley down to 5,000 rpm.
I then tried playing with the Rav valves (which I had taken out and cleaned a few days ago) and where set level with the black casing. Screwed both down 1 full turn, no noticeable difference, screwed to 1/2 turn up from original, no noticeable difference.
In the end I screwed them down 2 full turns and revs now go to 5,500 - 6,000 rpm and much quicker to plane with 1 person (probably 50 yards) so I'm thinking I'm on the right track.
My problem is knowing how far down I can go with the Ravs without causing something some damage.
Motor has been rebuilt 15 hrs ago but around 2000-3000 rpm is very lumpy.
I can't find the adjustments on the Carby (even removing the) air intake the rear carby has some adjustment screw on top which is 1/4 turn out but the other carby's hidden under motor parts. I would think they would be in a place easily accessible so i must be looking in the wrong place.
I would appeciate any help on any of the above (if you are still awake after reading all this)
I've certainly learnt alot about this boat in the last 2 weeks so I guess that's a good thing but frustrating.
Robert
Mainly my problem is knowing how far down I can screw the RAV valves without causing something damage & how to adjust the carbys.
1st time out with the boat 2 weeks ago it was very slow to plane with 1 person and for a breif period got to around 35 mph after quite a bit of time, but mostly 28-30 mph.
2 People in it was much worse and wouldn't plane doing around 25 mph, 3 people 20 mph.
Revs at 3/4 throttle was 5000 rpm and full throttle still 5,000 rpm.
I was told by the Jetski mechanic it might be the drive shaft carbon seal.
When I pulled the pump off I found there was around 45-50 thou clearance between the impeller and the wear ring.
what I have done so far is:
Replaced wear ring with a new one and put in a used standard impeller with straight blades, the one in there was a seadoo swirl impeller (which was apparently offered as better performance) but had worn around the outside edge.
Replaced the neoprene boot seal between pump housing and hull.
Checked the drive shaft carbon seal which was OK and new 'O' rings on the Seal Carrier.
2nd time out today still slow extremely slow to plane (around 200-300 yards) but with 2 people eventually got up to 30-32 mph, with 1 person slightly faster but still slow to plane. Revs at 3/4 throttle was still 5000 rpm and full throttle no better at 5,000 rpm.
What i found was if i turned hard right and crossed the wake i could get the revs up to the 7000 limiter and it was accelerating but as it started to grip revs dropped immediatley down to 5,000 rpm.
I then tried playing with the Rav valves (which I had taken out and cleaned a few days ago) and where set level with the black casing. Screwed both down 1 full turn, no noticeable difference, screwed to 1/2 turn up from original, no noticeable difference.
In the end I screwed them down 2 full turns and revs now go to 5,500 - 6,000 rpm and much quicker to plane with 1 person (probably 50 yards) so I'm thinking I'm on the right track.
My problem is knowing how far down I can go with the Ravs without causing something some damage.
Motor has been rebuilt 15 hrs ago but around 2000-3000 rpm is very lumpy.
I can't find the adjustments on the Carby (even removing the) air intake the rear carby has some adjustment screw on top which is 1/4 turn out but the other carby's hidden under motor parts. I would think they would be in a place easily accessible so i must be looking in the wrong place.
I would appeciate any help on any of the above (if you are still awake after reading all this)

I've certainly learnt alot about this boat in the last 2 weeks so I guess that's a good thing but frustrating.
Robert