2 replies to this topic

[lmgray]

1999 Seadoo Challenger 1800 w/twin 787's...  late last season, was having trouble with engines not going over about 4K RPM.  I learned a common cause is dirty rave valves -- I'm embarrassed to say, in 11 years, they've never been cleaned. When I removed them to clean, I found 1 was broken! A piece about 1" x 1/2" was missing from the bottom corner  DSC05762.JPG   62.85KB   5 downloads.  The "wound" has carbon build-up on it so I suspect this happened some time ago. There's no sign of the missing piece in the slot (tried inserting one of the others -- no obstruction).

 

Should I be concerned that the piece might have caused piston/cylinder damage or, should I replace the broken rave valve and, if it runs OK, assume the piece got blown out the exhaust? Where else would it have gone?

 

Is there a way to check for piston/cylinder damage without removing the head (which I consider beyond my general mechanical abilities...)?  I was thinking maybe a compression test -- thinking if compression is OK, it's not likely there was any piston/cyclinder damage?

[sweetchallenger]

I had a broken rave that looked just like yours. You need not worry. There is a 99.9% likelihood the broken piece(s) are laying innocently at the bottom of your muffler where they're not likely to do any harm. The reason is that the gasses exit the combustion chamber with extreme pressure into the exhaust. The pressure that helped the piece of rave valve break off likely aso carried it away. Good luck!

[BigWayne]

I agree the borken piece has likely just passed through the exhaust, but I would suggest pulling the head to inspect the piston heads, cillinder scoring, and ring seating. Pulling the head is quick, simple, and can save you tons of headache if you happen to find an issue.