1998 sportster 1800 cavitation after carbon ring, booth and oring change

[frederic.kustcher]

Good afternoon folks

I have a 98 Sporster 1800 twin engin and it's been cavitation so last year i replaced the carbon ring, o'rings and booth on both shaft and when i drop it in the water, it was still cavitating??? so i chaned the wear ring..the boat is 20 year gess it's time and remade the seal around the pump and still cavitating...so in an effort to see what is wrong, i really pushed back on the booth to get the c-clip to the second groove(that was painfull) and drop the both in the water...first at full throttle, it cavitated on both engin again..so i kept on tring a few time and it finnaly got going no cavitating for the rest of the day...my thought was that everthing placed it self and it was good.... but today i drop the boat again and did the same for about 5 min that got going for the rest of the day...i'm going crasy...what else i am missing...anyone that might have had this issue why it's cavitating and stop?

thanks!

 

[Dr Honda]

If you have new carbon seals, and they are tight... then we have to look for air somewhere else.

1) Are there cracks on the fittings in the hull where the carbon seal boots attach?

2) Are the boots in good shape? (any holes)

3) When you put the pumps back on... did you use new neoprene gaskets? (I'm guessing this is where your problem is)

4) What do your impellers look like?

5) What do your wear rings look like?

 

[frederic.kustcher]

thanks for your answer, see mine in red

If you have new carbon seals, and they are tight... then we have to look for air somewhere else.

1) Are there cracks on the fittings in the hull where the carbon seal boots attach? No Cracks and cavitation stops after a few try at full throttle has long has the boat stay in the water

2) Are the boots in good shape? (any holes) they are brand new, changed with the carbon ring

3) When you put the pumps back on... did you use new neoprene gaskets? (I'm guessing this is where your problem is)...BRP told me to use selicon that they were not putting neopren anymore and they were none when i removed the pump..i have look online and i will order them from the web... that was my guess too cause all the rest checks out

4) What do your impellers look like? One is new (2 years due to a rock) and they are in good condition no dents and not bent.

5) What do your wear rings look like? brand new and changed before doing this post

thanks i will get back to you if the neopren seal does not do the job

 

[Dr Honda]

Ok... I hate dealers. The neoprene seals are all the same for the 140 pump. Some boats/pwc show them... and some don't. Most guys behind the parts counter are too lazy to look up the part if it's not on the shelf or on your diagram. Using RTV is BAD. First... it may not seal. (have a leak) and it makes it a real pain in the ass to get the pump off the next time. Not to mention... you have to clean everything to get the proper seal in.


Anyway... when you have the pumps off... clean around the shoe really well with soap, water and a stiff bristle brush. Then, pump in a bead of RTV around the shoe. THat way, we know air isn't bypassing.


Hey... does your boat have the weedless grates? (with a cable to push them down?) If it does... it could be sucking air past the cables.

 

[frederic.kustcher]

well reaceved the neopren seal did what you said....still the same..boat cavitate then stop and goes well...today it was going well after a rought start on the lake and it was ok for a good part of the day and i stop to have the passanger change place and it would not take off after...it was a pain to get it going again... guess the weedless gate are my next step...not sure what to do with them...i don't even use them...