Wear ring contact with prop for GSX 787

[PolarCelsius]

My wear ring makes contact with my factory prop, the prop is in slightly questionable shape with some rugged edges here and there, I sanded them down for the most part

The prop has a small but noticable gap between itself and the wear ring for most of the 'clockface but at the 5-o'clock position the blade makes contact with the wear ring and destroys that portion of the wear ring almost immediately. I can not turn the prop by hand, I've heard people suggest to just run it and it will shave away the excess, but it does more than just shave, it gouges and chips the ring. I've gone thru 2 wear rings because of this

The Question:
Is it the wear rings fault, the props fault, or the housings fault?

If so the ring, should I sand down the surface of a new ring at the 5-o'clock position?

If so the housing, should I sand down the housing?

If so the prop which Solas prop is recommended for a 96' GSX 787?


Waiting patiently for the legendary mikidymac to chime in with his ever expansive retro two-banger knowledge

 

[mikidymac]

I would send your prop off to be refurbished. Sounds like it’s pretty bent.

 

[PolarCelsius]

I would send your prop off to be refurbished. Sounds like it’s pretty bent.

Yeah it could be because it's bent, I could try bending it myself, but the thing is-

The prop always makes contact in the same spot on the wear ring, if the prop was out of alignment wouldn't it make contact all the way around?

 

[mikidymac]

You would think. Any corrosion on the pump housing?

 

[IDoSeaDoo]

You said this is the second wear ring that is doing this same thing? I'd say your pump is dented in at that position. And the impeller doesn't do a good job shaving it down? Strange. Those derlin rings should shave pretty well. I always see them with lots of grooves shaved by small rocks or shells that enter the pump and get lodged. I'd say that's your best way of reshaping a wear ring. Otherwise, it sounds like maybe you need another pump. Or perhaps a stainless wear ring?

 

[PolarCelsius]

It shaves a groove when I start the engine but after the first ride the cavitation comes back and the ring is chipped right where the impeller dug

I think you're right about the housing being dented or something, I could try measuring it to make sure and if so then maybe take a hammer to it, or possibly just sand it down, or even sand down the wear ring before the impeller can take a chunk out of it

I definitely considered a stainless wear ring, but I think in order to get the impeller to rotate freely I'll have to really grind down one of the fins, creating a huge gap for the rest of the 'clockface

Once I get this apart I'll take some pictures

 

[PolarCelsius]

 

[PolarCelsius]

You would think. Any corrosion on the pump housing?

Nah no corrosion anywhere, I believe it was a fresh water ski all it's life, the housing seems to be in great condition, (I haven't measured it yet though)

I wonder if I just got unlucky with the rings, the first one was the one I bought the ski with so it was already similarly damaged, then the second, I have a third on the way

I can try having faith in the new ring, Could I lube the ring with something Incase I need to slip it out without damaging it and make an adjustment? The last ring I had to take out was a nightmare getting it out

 

[mikidymac]

Could be a bent pump shaft.

 

[PolarCelsius]

The impeller trailing fins seem to be odly bent, should I bend these to be more flat like the last picture?

 

[PolarCelsius]

Could be a bent pump shaft.

The shaft seems to be true and straight

 

[mikidymac]

Then that leaves the impeller since you can't dent the brass pump that I have ever seen.

 

[PolarCelsius]

The fins on the impeller don't look good but with those bent inward like that it would mean that the fins would have more clearance from the wear ring, lessening the distance by curving, that would help explain the cavitation but not the oblong wear ring contact issue

What I found:

After taking out this wear ring I have found that the previous owner used a saw like method to extract the wear ring, cutting into the housing, and then attempting to fill the gap with something

Although this is not in the exact spot of were the impeller was making contact (but right next to it) I have reason to believe this is where the oblong pressure is coming from, I'm going to sand this down

 

[AKnarrowback]

The original aluminum pumps had a groove cast into the pump that allowed you to cut the liner out without digging into the pump body. This was back before the neoprene rings were thought of and a light bead of silicone was used to seal the pump to the hull. We just put a little extra sealant in the end of the groove on the sealing end and never had a problem with ventilation.

Take the pump you have, smooth out the inner diameter where the liner slides in so the liner sets in even all around and run it.

My brass pump has had a hand full of liners all cut out by a sawzall leaving a little groove each time. I file things smooth, set the liner in straight, make sure the neoprene ring is good to seal and run it without any ventilation problems.

You do not want anything making that pump inner diameter small than spec or the liner is going to on have one direction to go when you cram it in there.

 

[PolarCelsius]

Sanded the pump housing, this should definitely make a difference

I have a new wear ring and a Solas Concord SD-CD 15/23 Impeller on the way since my impeller has seen better days, and I couldn't manipulate the fins at all, I should also enjoy the better hole shot of this design as top end is not my riding style

 

[PolarCelsius]

SOLUTION

Wear ring making contact with the impeller was due to the unsanded filling of the saw cut, for those who can't turn their impeller by hand, do not rely on the engine to gouge your wear ring when you start it up, fix the issue! sand the housing down!

Wanted to reiterate the fact that my old impeller ALSO fit great after doing this, but now I use the Solas impeller as my stock one wasn't very pretty, so much less cavitation out of the hole!

Picture showcasing a successful day out on the lake, that's the face of a man with no cavitation

 

[AKnarrowback]

Awesome to hear!

Sweet looking machine BTW.