2001 Virage 700 Engine Vibration

[Myself]

Have you checked the runout on the driveshaft? Somebody sucking a tube rope up WILL bend them sometimes. I had a customer a couple years back that had bent driveshafts on BOTH of their Seadoos.

[Bluedmax]

No I haven’t checked that, but we’ve never sucked anything significant like a rope since new. Only a few twigs here and there, which have been easy cleared by using reverse. The ski also runs smoothly otherwise. I’ll check it if you think this is a contributing factor to the exhaust bolts snapping, but would need some guidance how to check.

When working on automotive engines through my years, I’ve always been told the importance of flat mating surfaces for manifolds. I have to think a 0.013 difference between the surfaces of the 2 jugs is not good and is contributing to the issue?

[Myself]

That could be it. I know that as a part of assembly, you are supposed to install the exhaust manifold without gaskets installed before the the cylinder nuts are torqued to spec, so that everything is aligned perfectly.

This is how it should be done on ALL multi cylinder engines that have seperated jugs.

[Bluedmax]

I called SBT. Of course they said that variance isn’t right and to send it back. They want to inspect the motor, make sure the replacement engine doesn’t have the same problem, then send out a new one. Guess I get to R&R the engine a second time

[casey67]

I called SBT. Of course they said that variance isn’t right and to send it back. They want to inspect the motor, make sure the replacement engine doesn’t have the same problem, then send out a new one. Guess I get to R&R the engine a second time

Yeah, but eliminates any question/doubts about water and rust. Big win in my book.

[Bluedmax]

Yes I agree. I’ll just have to pay shipping to return this engine to them (their policy) which I’m guessing will prob be about $150-200. Of course I would prefer everything to have worked right the first time, but was nice to have the 1 year warranty “insurance”. I need to get it turned back around soon though, because the 1 year warranty still expires end of September, even with the replacement engine.

[Bluedmax]

Back again with another troubling find. I pulled the engine tonight and got it all stripped down to ship off. I took a quick peek through the intake ports and found the rear cylinder to have HEAVY grooves already worn into at least the bottom skirt of the piston. What the hell would have caused wear like this with only a few hours?? I attached a pic of the front piston also for reference, which looks fine.

[casey67]

Running hot because of the water leak. The cooling water enters the engine from the exhaust manifold.

[Myself]

Running hot because of the water leak. The cooling water enters the engine from the exhaust manifold.

Also, water entering the cylinder washes away the lube and scores up the cylinder.

[Bluedmax]

Ok that makes sense. Depending on how long the manifold was loose and leaking water, that cylinder could have been running hot and getting wet then. I'm hoping that's all it was.
But I also just realized I'm backwards with my cylinder identification. The scored / grooved cylinder was actually the front one and the rear is fine. I only mention this because the reason I pulled the original factory engine in the first place was because the front piston was completely damaged. Pieces of either ring or piston started smashing itself to pieces (see pic...). I'm not sure what would have caused that, but I'm a little concerned now that I've seen "issues" with the front piston on 2 different engines. Maybe these two situations are completely unrelated, but if there's another issue going on with the ski (cooling, oil, other??) I obviously want to correct it now before I get another replacement engine.