96 sportster cavitation???

[tbutt130]

Forgot to mention in my last post that later in my drive, even when the motor was developing good power it would pull some then the motor would rev higher and it would stop pulling. Looks like i have some work ahead of me. What causes this?

 

[Dr Honda]

Bad carbon ring, leak around the pump, leak around the pump shoe, bad impeller, bad wear ring.

Your leak can be coming from any of those places.

 

[tbutt130]

Where do I start? If it helps to diagnose, there was some water in the engine compartment that I thought was getting kicked up into the air intake and causing my other issue. So I bailed most of it out and that's when the cavitation started.

 

[Dr Honda]

Where do I start?.

since your boat is older... I would jut buy a wear ring and a carbon seal, and do them both at the same time. also, you can seal up anything else you find along the way

If it helps to diagnose, there was some water in the engine compartment that I thought was getting kicked up into the air intake and causing my other issue. So I bailed most of it out and that's when the cavitation started.

thees boats take on more water than people think they should. I have an almost new carbon ring, and I will drain out about 2 gallons after a day on the water.

 

[tbutt130]

Thanks for the replies. I have seen lots of instructions here for the wear ring replacement. Doesn't seem too bad....How about the carbon seal replacement? Can't seem to find much about how to replace that. Other then the actual wear ring and carbon seal, are there any other miscellaneous parts I will need for success?

 

[Dr Honda]

.... are there any other miscellaneous parts I will need for success?

Yes. You will want to get a neoprene seal. It's a simple foam seal that goes between the pump and the pump shoe. Even at the dealer it's only $5 gasket. Also, replace the 2 o-rings that are in the stainless ring, and buy a new C-clip that hold it in place. (you may have a third O-ring to hold it in place)

To do your carbon ring: (before you remove the pump)

1) slide the stainless ring toward the rear, and remove the C-clip or cut the O-ring that holds it in place, and remove the clamp that holds the PTO boot to the drive shaft.

2) remove the pump, and slide out the driveshaft.

3) remove the clamp holding the Carbon ring, and replace the carbon ring.

4) replace the 2 O-rings in the stainless ring. (and grease them)

5) reassemble, use a zip tie to hold the PTO boot to the driveshaft, and grease the PTO.

Easy.


Needless to say... before you put the pump back on... do the wear ring, and inspect everything.

 

[pincusa]

Honda outlined what you needed. I'll only add that you should also replace the bellows that hold the ring. It is what presses the ring onto the SS collar and gets hard with time. Also, make sure the SS collar is PERFECTLY smooth and free of any grease. If it's not, refinish it or replace it.

Carbon seals are easier than a wear ring. You can try to add some additional pressure to it by moving the bellows maybe 1/4" forward and retightening the hose clamp that holds it. Take it out for a ride and see if that changes anything. But that's a temp solution and only means that you should be replacing everything.

 

[tbutt130]

I got under the boat with a flashlight after work today. The wear ring is toast. I can't believe I ever got it to plane much less to nearly 40mph after looking at it. Looking at the impeller from the intake grate, the blades all have a few small nicks in them on the leading edge, but don't look bent or anything. Do I need a new impeller? Can (should) I use a dremel or a grinder to smooth out the nicks?

Next question...looking at the shaft that comes from the hull to the impeller, there is a black plastic ring that is just floating loosely on it. What is that for and do I need to replace it? Does this being loose indicate that there is anything else I need to do?

Thanks.