Waverunner 1200 XLT seized - again

[shane21]

Last summer bought a 2001 1200 XLT with seized engine. The oil line on the #3 cylinder had popped off which clearly had led to that that cylinder seizing. I rebuilt the top end with a complete SBT cylinder exchange, replaced all fuel lines, oil lines, oil line check valves, and rebuilt the carburetors. I ran it throuogh a meticulous break-in procedure and have put about 15-20 hours on it since break in. I checked plugs after every run and all indicated good mixture. Then the engine seized again. Initial inspection (looking at spark plugs and viewing piston head) indicated the #2 cylinder had seized this time and I feared oil starvation again. But after disassembly, I found that all oil lines were intact, oil was getting to the carbs and the cylinders appeared to be getting plenty of lubrication. However, the #2 piston had catastrophically failed and broken pieces of that piston were everywhere (in the cylinder, in the exhaust port, and in the crankcase.) I plan fix the ski again but don't want this to become a money pit..

Any ideas on what happened? Thoughts and recommendations appreciated.

Thanks!

[Technical Support]

Re: Waverunner 1200 XLT seized - again

Are you sure you got all the old parts from the first failure out of the exhaust system when you put the new top end kit on? Sometimes pieces will get sucked back into the engine if they are left in the pipe.

[shane21]

Re: Waverunner 1200 XLT seized - again

I believe so but I guess I can't be absolutely positive since I didn't see that much debris as I took everything apart the first time. I replaced the catalytic converter with a D-ring, and cleaned, brushed, and blew out any debris I could find in the exhaust manifold, muffler and exhaust pipe. Most of the debris I found was in the exhaust manifold and some of it was stopped by the catalytic converter. I also flushed and sucked out the crank case to remove any debris that had fallen down as a result of the first seizure. I suppose it is also possible that i missed something there? Since my first post, I have continued disassembly/diagnoses and taken the engine out of the ski. The #2 rod bearing (at the crankshaft) is destroyed (lots of play and binding) and the middle two tabs on the reed valve are bent, presumably where they were struck by the piston/parts as it flailed around in the cylinder. I assume this reed valve assembly will need to be replaced at a minimum and I am leaning to replace all three while I have it torn apart. thoughts? Are used valves OK as long as they are in good condition (not bent, chipped, damaged, etc?)

Thanks very much for your feedback..

[Technical Support]

Re: Waverunner 1200 XLT seized - again

Yep, sounds like crap might have resurfaced, replace the crank and clean up everything, if you find good flat used reeds then you can chance it, use all new seals and go from there.

[shane21]

Re: Waverunner 1200 XLT seized - again

I am actually contemplating a complete engine replacement, plus reed valves as required. I figure i will not spend much more in the short run and may be much safer in the long run. Any core concerns?

[Technical Support]

Re: Waverunner 1200 XLT seized - again

Send pics in if your in question of core damage or post the pics.