New Guy Trying to get on the Water

[S.T.B.]

Hi to the group, my name is Steve and thanks in advance for taking time to read my question. I just purchesed a 1997 GTX that sounded great on the hose in the driveway, only to find that it has a myriad of problems. First off, we left the hose run while checking out the craft at the sellers house and had a flooded engine as soon as I got home. Solved this and got on the water only to find that it won't go over 1/2 throttle w/o bogging.

Suspect fuel plugging so replaced lines and external filter and cleaned switch and carbs. Lots of crud in switch.
Back on water, ran good for 30 min then it would "freewheel" over 1/2 throttle. Engine sounded great, rpms were high, but no thrust ! We stopped and I jumped in to look underneath, but only a very minimal amount of seagrass.

It acted like this all the way back to the dock. At home it still looked clear and the shaft has no play and wear ring has close fit to the impeller.
These were the most likely solutions according to the archives that I could find.
If anyone has any other suspects it would be great.
It's becoming a head scratcher.

Also found a broken steering rod in back on the left side, must have been that way for a while as the sheared end was rusted over. It didn't seem to affect the operation any but will need fixing, any tips here ?

Thanks.

Steve

 

[bigJake]

if the wear ring is good, the other likely cause of cavitation is the carbon ring. #8 in this diagram. if the carbon ring is not getting a good seal against the stainless steel ring, it will suck air. you can try putting a zip tie on the center of the bellows to put more pressure on the carbon ring to help verify that is the issue. http://fiche.seadoowarehouse.com/se...make=seadoopwc&a=258&b=18&c=0&d=-DRIVE-SYSTEM

 

[Coastiejoe]

I'm with Jake.

If you are certain there is nothing wrapped in the impeller area, it really has to be the carbon seal area or a wiped out wear ring.

The gap should be no larger than the width of a dime.

 

[S.T.B.]

Thanks for the info, I'll do the ty wrap and put it back in water Tues night. Will that be enough to compress the carbon ring though ? I can get a hose clamp and pad it if that would be better.
As for the wear ring gap, yes definitely smaller than a dime. If it matters - the edge of the impeller as seen from the intake grate looking back is not completely smooth on any of the 3 blades. No chunks missing, but small uneven divots and roughness.


Steve

 

[Coastiejoe]

Thanks for the info, I'll do the ty wrap and put it back in water Tues night. Will that be enough to compress the carbon ring though ? I can get a hose clamp and pad it if that would be better.
As for the wear ring gap, yes definitely smaller than a dime. If it matters - the edge of the impeller as seen from the intake grate looking back is not completely smooth on any of the 3 blades. No chunks missing, but small uneven divots and roughness.


Steve

Tiny damage will not seriously affect the performance. Air coming through the seal from the hull can.

The wire tie trick works pretty well. At the very least it will help you determine if it is your issue.

 

[S.T.B.]

I put 2 Ty-wraps around the 2 center grooves in the boot as tight as I could get them. It did make a difference, the ski hit 51 mph max.
After 20 min of riding, performance slipped some and no pick up from a standstill. We had to "milk" it to get up around 40. So is the verdict to change out the carbon ring ? And if so, what would be good to go after while it is apart ?

Thanks for direction to the smoking gun.

Steve

 

[bigJake]

Since your cavitation is so bad, it may be a good idea to replace the rubber boot and the stainless steel ring in addition to the carbon ring. Also, the o-ring that holds the carbon ring in place has been superceded with a circ-clip because the o-ring may fail, so I would replace that while it is apart. When you pull the driveshaft, make sure you don't lose the rubber bumpers off the ends.

Also, while it is apart check the pump and the condition of the impeller. make sure the impeller spins freely and you don't have a pump bearing going bad. I don't think your ski comes original with a neoprene seal between the pump housing and the hull, it is probably sealed with RTV. Order a neoprene seal to avoid having to use the rtv and make it simpler to remove the next time.

If you haven't already, you will want to replace the oil in the pump cone and a new o-ring.

Some other basic maintenance items if you haven't already done so are, clean the Rave valves and replace the o-rings, replace the small oil injection lines with 3/32 Tygon tubing and clean the water control valve.

Some of the part numbers:
[h=5]SeaDoo Pump Cone O'Ring 293300011[/h][h=5]SeaDoo Neoprene Pump Seal 293200024[/h][h=5]SeaDoo Driveshaft C' Clip #272000135[/h][h=5]SeaDoo 787cc Carb Engine Rave Valve O-Ring 420430110[/h][h=5]SeaDoo 787cc Rave Valve Gasket Carb Engine 420931540[/h]