Max speed 7mph

[Sportster-2001-951C-Stock]

The carbon ring ID isn't egg shaped, must not be worn much. Does look like a scratch or gouge on the face?

The carbon ring seals against the stainless ring (collar) to keep water out of the hull but more importantly has tension from the rubber bellows to keep air from being sucked from inside the bilge into the impeller. Too much air makes the impeller slip like pressing on a manual transmission clutch.

If the carbon ring is in good condition, you can replace just the bellows. Maybe someone was running the engine on the trailer and overheated the rubber bellows due to friction, bellows tension was compromised. The carbon ring face must seal against the stainless ring face so make sure the stainless ring isn't warped or something. The stainless ring is sealed to the drive shaft by o-ring. If the o-ring is missing, an air leak occurs, probably a water leak as well.

You can lay some fine sandpaper on flat glass, tape it to the glass, and resurface minor imperfections in the carbon ring face by moving the piece in a figure-8 pattern to keep it flat across the face. Choose paper based on how deep the imperfections are, but final finish with fine paper, maybe 1600 grit. Wet paper is good for this, with some water to keep chunks from forming and scratching your work piece.

There are many places you can order parts, the sponsor of this site above links if that's your preference.

 

[Sportster-2001-951C-Stock]

One other question I just thought of, how much clearance is between your impeller blades and the wear ring, less than or around the thickness of a dime or much more?

 

[mikidymac]

No. That’s about correct. The face should be smooth and flat.

 

[Seadoo Brian]

One other question I just thought of, how much clearance is between your impeller blades and the wear ring, less than or around the thickness of a dime or much more?

Less than a dime, I couldn't get a 4 thousandths feeler gauge in between the impeller and new wear ring. The pic with the carbon ring on the shaft shoulder has a lot of play, how tight should it be?

 

[Sportster-2001-951C-Stock]

The ID of the carbon ring must be larger than the shaft, yet small enough to keep the carbon face reasonably centered with the stainless ring to minimize air leaks. If air can pass through this flat-on-flat sealing surface it gets ingested into the impeller. Also if for instance there a hole in the bellows or not enough tension to keep the faces against each other, air can pass from the bilge into the impeller.

Of course, full torque from the engine must be transferred through the shaft into the impeller as well, so if for instance the splines were worn and slipping, the engine RPM might not be the identical to impeller RPM but much higher.

 

[Sportster-2001-951C-Stock]

Less than a dime, I couldn't get a 4 thousandths feeler gauge in between the impeller and new wear ring. The pic with the carbon ring on the shaft shoulder has a lot of play, how tight should it be?

This is very good, less than the thickness of a dime is fine.

 

[mikidymac]

The clearance between your shaft and ring is normal.