Will a bad carbon ring sink a boat?

[tommy1976]

Hi there:

Got my 1998 challenger on the lake yesterday and on one engine there is a slight leak from the carbon ring assembly. Its not too bad and if I turn on the sump pump every 15 min or so it clears it out with a matter of seconds. If I reach down there and pull the rubber boot back from the silver fitting then water seems to gush in at a much faster rate but as soon as I release the rubber boot it goes back to a trickle.

I'm only finding this on one engine. The other doesn't leak at all - even if I push the rubber boot back.

Wanted to know if this is normal and if you can run it like this for a while - ie: will a bad carbon ring create enough of a leak to sink the boat? Was hoping to wait till the end of the season before I start pulling this stuff apart.

Many thanks in advance for all your advise.

 

[seadooya]

replace the carbon ring. Not only is it leaking, butthe pump will draw air, causing that side to cavitate.

 

[Dr Honda]

To answer your question... Yes, it can sink quickly if you have a catastrophic failure of the driveshaft seal. BUT... it's very unlikely for a carbon seal to die like that.

With the early seal pack, they could seize to the driveshaft, and twist the boot off the hull. It was common for them to fail like that, and sink your boat/PWC. That is why Bombardier switched to a carbon seal. They will leak, and cause cavitation, but not fail to the point of sinking. (they are safer)

 

[scooper77515]

The boot is acting as a pressurizing spring to keep the carbon against the seal. So that is acting as it should.

It will leak a bit when running and shoot a fine spray mist in the engine compartment, and that too is normal and keeps the seal cool.

But it should be pretty hard to pull that boot back. It shouldn't just pull back with a light hand, but require maybe 20 lbs pressure to pull it. It should be compressed a bit to keep good pressure on the seal. You may have to move the o-ring or clip that keeps it retained one "click" or notch forward toward the seal to make it have more pressure.

Compare the pressure to the other engine and see if the boot looks longer or shorter than the other one (ie. less or more compressed).

 

[tommy1976]

The boot is acting as a pressurizing spring to keep the carbon against the seal. So that is acting as it should.

It will leak a bit when running and shoot a fine spray mist in the engine compartment, and that too is normal and keeps the seal cool.

But it should be pretty hard to pull that boot back. It shouldn't just pull back with a light hand, but require maybe 20 lbs pressure to pull it. It should be compressed a bit to keep good pressure on the seal. You may have to move the o-ring or clip that keeps it retained one "click" or notch forward toward the seal to make it have more pressure.

Compare the pressure to the other engine and see if the boot looks longer or shorter than the other one (ie. less or more compressed).

No - something is definately wonkey then. It trickles when the boat is sitting (engines not running) and if I push back with my hands it gushes - but there is no way I'm applying 20 pounds of force. Its quite easy to move the boot back to get water flow.

Question - what actually holds the silver ring seal carrier to the driveshaft and the circlip in place? In the following pic - i'm not able to move the silver item next to the carbon ring (highlighted) along the axis of the shaft at all. Is there somethign I'm missing? How can I get this driveshaft out to replace the seal??!?!?

 

[seadooya]

the second arrow, pointingto the clip, pop that off, its a C-clip, then the little clamp around the dustboot, off the pto, removethat, then remove pump assy, and driveshaft will fall out.

 

[scooper77515]

The carbon appears damaged. Right smack in the middle of your picture. There is a chunk missing off the carbon ring. That crap is brittle. Worked with them on jetboats and vacuum pumps and compressors. If you even have that one chip missing, you most likely have much more damage on the working face of the seal.

I am guessing that you have chips in the mating face letting water seep past.

The boot appears to be plenty compressed to put appropriate pressure to the seal. So pull it back and see if there are any grooves or chips missing from the mating face of the seal. If so, time to replace.

 

[tommy1976]

No - something is definately wonkey then. It trickles when the boat is sitting (engines not running) and if I push back with my hands it gushes - but there is no way I'm applying 20 pounds of force. Its quite easy to move the boot back to get water flow.

Question - what actually holds the silver ring seal carrier to the driveshaft and the circlip in place? In the following pic - i'm not able to move the silver item next to the carbon ring (highlighted) along the axis of the shaft at all. Is there somethign I'm missing? How can I get this driveshaft out to replace the seal??!?!?

Hi everyone - and thanks for all the GREAT advise.

Sorry - if I wasn't clear in my post. The pic above is from the seadoo manual. On my boat it looks the same but I can't budge the seal carreir towards the back of the boat to expose the C-CLIP. The seal carrier seems to be stuck on the driveshaft - any advise on how to fix? can I just hammer it out?

 

[seadooya]

spin it with a pipe wrench. Theres 2-o-rings inside the steel collar, that arent budging.

 

[scooper77515]

Duh, that chip is not on the working surface of that ring anyways