RESTO Impeller/Ring/Assembly Troubleshooting

[RocketFox650]

Hey ski fans! My skis seem to house fricken gremlins, so I'm trying to break up problems by area. I'm on season 3 with a 97½ GSX and a 95? SP. I've had this weird issue since the start where occasionally either ski will rev out with barely any acceleration whatsoever. At the end of the first year, the battery was too much of an issue and I trailered the SP for the day and tried to double up on my GSX. Every time my gf got on, it would start that rev out nonsense. I'd drop her, restart it, and play with the throttle until I came back to life. In the end, I gave up and trailered it for the year. Year 2, late start and I decided to try running it again to see what happened. Somehow, sitting 6 months, it now wallows at takeoff until 25mph area then planes out, but I've lost about 10mph off the top. The SP did it's rev out thing a couple times that summer, but otherwise no real issues.

Now I know my VTS never worked, but last year I had an electrical gremlin and the fuse to it was changed out and system played with trying to diagnose a no start/no beep/no lights situation. The motor is shorted out, but if I remember correctly, the VTS gauge would indicate down with button, but nothing up with button/blown fuse. I've always assumed I needed to do a ring and impeller more or less, but the intermittent nature of the issue had always confounded me. I've googled for hours and found others with this issue, but never found a solution.

Anyways, I pulled out all my assemblies, checked impellers and rings. I'll post pictures by ski, with what I've found and questions as they pertain to each.

 

[RocketFox650]

This is the GSX impeller and ring, followed by the back side of the assembly. I don't have the removal tool yet, as they come with impellers, and I have an extra impeller as it is, and am trying to decide that exact issue right now.

As you can see, the impeller is beat to hell, as expected. The pump assembly so far appears to possibly have minor dings internally at the back of the impeller. To my eyes, the clearances and condition of the wear ring truly doesn't seem to be an issue.

My thoughts have always been that the wallow was a jet angle issue I need to manually correct. The intermittent rev out/cavitation, maybe something about needing to impeller to start and stop until it "catches" and creates a jet? I'm trying to physics this with a little common sense, and I'm wondering if the disposition of weight, the wake, water conditions, etc create an assortment of variables that all have to meet up correctly to have the jet flow, and shutting it down allowed it to try try try again until it caught. Putting 160# extra out back caused it every time and removing it eventually corrected it, so I'm working with that as a clue right this second and guessing here.

My thoughts- Replace/grind a prop, adjust jet, maybe the wear ring to correct this issue.

 

[RocketFox650]

Here we have the SP assembly. Again, the wear ring seems worn, but by no means thrashed. Again, this is my first rodeo, so I'm in no way positive. This could be enough wear to be a massive issue as far as I know. The impeller seems to be in at least fair condition. Having it apart, I'll remove it fully and address anything I find underlying. Again, there's a single minor ding at the back of the impeller on the pump housing, approx 0.5mm x 1mm. On closer inspection, I do see a scar ½" up the ring from the back, measuring under 1mm deep, traveling the entire circumference. One blade has some light gouges/good scratches on the back side about mid blade.

Removing the assembly, I found it's a bit different than the GSX, as it has connections that penetrate the hull, instead of the seals at the housing. Somebody siliconed the shit out of the top seal where those penetrations are and there's decayed plant matter on the mating ring that potentially was there when I removed it. I set it on the back of my ski near the foot well, which is full of leaf debris right now, so I can't say for sure. The RTV is only applied around those thru hull connections.

Thoughts- wear ring is causing that intermittent cavitation at that scarred point similar to the impeller situation on the GSX. Additionally, no real seal besides the wear ring to the plastic mating surface, RTV is preventing a full seal and blow by creates a situation that contributes as a factor to making a proper jet, sometimes resulting in cavitation.

 

[RocketFox650]

This is a spare SS impeller I have. You can see there's a good ding and a gouge on the backside of one blade. Instead of buying another impeller, it seems that I may be able to use this on the GSX if I have it repaired, assuming it's feasible. Any thoughts here are welcome. As you can see the wear ring is gone. My 4th housing is much the same with no impeller in it. Big pieces of the fins missing.

On my GSX, there's a large cone seal where the shaft mates to the impeller. The spare SS one had a smaller donut seal as well, but it's dry rotted. The SP has a Skat Track on it with no seal. There's a sort of rusty grease on the GSX splines at the seal point, same with the SS. The Skat is beautifully clean and shiny, and I verified again, there is no seal or boot on the shaft or the impeller.

On the SP, between the 2 housing pieces, there's supposed to be 2 o-rings, only 1 of which I recovered, but that's most likely because I wasn't aware they were there until I found one in my lap. Every write up I've test indicates there's a neoprene gasket somewhere in these, I assume at the hull mating surface, unless someone shady tree RTVd it. No sign of any further gaskets or seals at this point.

 

[RocketFox650]

GSX mating plate/adapter. Output shaft has a rubber plug at the tip, bit of moist rusty grease inside. The splines seem ground down, or flared out as it would mate to the impeller. Kind of a bell shape or hour glass. Plastic surface at base is scratched up, but actually not that deep. Appears mostly cosmetic, but again idk the tolerances here, so that <0.5mm scratch may be serious. Output shaft is not rigidly in place, there's play in it like a driveshaft, but limited to about ½" of travel in every direction. With a VTS I'm sure it has to be mobile, but tell me if I'm wrong.

 

[RocketFox650]

SP surface doesn't have the same adapter and has those penetrations. Mating surface doesn't look terrible. I really don't like the RTV here. It's not gonna mate and seal well. Shaft has same plug, clean inside. Ridgid in place, but this is a fixed jet. The splines don't continue into that Bell shape, but it occurs to me that the GSX shaft having to move is going to change the angles in stuff and the impeller either needs a slightly longer spline length with the unusual shape to function, or it's wore itself that way because of the same reasons. If it's wear, someone chime in on if it should be replaced.

 

[RocketFox650]

I have a 96 GSX and 95 GTX I need to water test still, tho everything looks decent assembled. Idk if I should start pulling them apart anyways considering how easy it is to do. I'm not keeping the GTX anyways (or the SP, but it's been an issue so I pulled it to see. Discovered a Skat Track impeller and a spare SS impeller, as well as 2 extra housings, and gf says there's also a bin full of more goodies). I have to put it in the water to swap trailers anyways, so all 4 are going in together. I mean I can reasonably say I'm selling them, it's not my problem. They fire up and run. But man, I'd be so disappointed if the first set I'd bought seemed great until I put them in and the jets failed. I had to learn marine repair, and SeaDoo specifics eventually, but at the start it was a whole new world and I wouldn't have known what to do. Would have figured they were junk or needed a full rebuild. I don't wanna do that to someone else. That's shitty. I've had a quad sale go sideways once because I couldn't see the cracks in the case from the crank. The guy painted over it and I didn't find it until spring. Hell, I still have 2 entire Polaris Predator 500s, standard and TLD, plus a third engine, and about $3k into it, having never ridden one. I'm rambling now, but points the same. I'd rather be confident selling them.

Next issue and new thread, coming soon!