Lost Allen screw - could in be in the crankcase ?

[GT6Racer]

Hi, I was rebuilding the carbs on my 1995 XP with my son. We had had put the two short Allen screws that hold the air box bracket loosely in their holes on the head to remember that they are the short ones. Anyway, we got it back together, and fired it up ( ran great ) before installing the intake beyond the carbs. After shutting it off we notice one of the screws loosely fitted to the head has disappeared. We cannot find it anywhere. So, fearing the worst we pulled off the carbs and rotary valve. The rotary valve disc and ports looks great, no dents or marks, and no sign of the screw or any witness marks on the crank that indicate its presence. The crank turns freely.
Do you think it is possible the screw could have gone though the rotary valve fast enough not to have gotten caught, and that it now sits somewhere in the crankcase - Ie is there somewhere it could be sitting and not being hit by the crank?
Of course, I’m debating if I need to pull the motor and open it up.
Any advice is appreciated,,

Thanks, Andrew

 

[Cheflen]

Personally, I believe there is no way that screw is in there if it hasn't left any mark, if you haven't heard any knocking, if there isn't a huge hole in your crankcase, and your rotary valve is clean. I just had one of those screws fall out while the engine was running and it got stuck in the rotary valve and bent the crap out of it. If it runs without any noises I don't think there's anything in there

 

[GT6Racer]

Thanks. That’s what I would have expected. I’d also have expected marks all over the crank if it was bouncing around in there, but I see nothing. Seems a shame to risk killing the ski, but I’m thinking I’ll just put It back together and cross my fingers...

 

[Cheflen]

Thanks. That’s what I would have expected. I’d also have expected marks all over the crank if it was bouncing around in there, but I see nothing. Seems a shame to risk killing the ski, but I’m thinking I’ll just put It back together and cross my fingers...

Well I would think that the biggest risk was the first start up and that has already passed

 

[Sportster-2001-951C-Stock]

I seriously doubt the screw could make it past the RV without reeking havoc on the RV as well, but if by some slim chance it could've then certainly it would bounce around in the crankcase and make a lot of racket.

My feeling is it's in the bilge but was this screw in a location where it would've been funneled into the carb intake if it did rattle loose? It would have to make it past the butterfly inside the carb in order to get into the RV, maybe it's still in the carb throat?

 

[GT6Racer]

Being on the head, and the intake off, the falling path to the carb inlet is quite likely. It wasn’t in the carb throat, and as I’ve had it running, the carb had been operated. I also now think it must be somewhere in the bilge, but we have looked everywhere, even using my endoscope. Of course, things are very good at hiding inside the hull - no access to see under the engine or in the bilge, and lots of places to hide. We’ve had it tipped both ways, still nothing shows up. Today I’m going to take one more peak into the crankcase with the endoscope, then put it back together and see what happens..

 

[GT6Racer]

Well, I put it together, cranked over w/o plugs and then fired it up. No strange noises and seems to run fine, other than longer than usual overrun so may have air leak somewhere. Provided that leak is not due to a screw sticking through the crankcase it seems to be fine.. Still no sign of the screw... thanks for your input ! Andrew

 

[AKnarrowback]

The great thing about a SeaDoo when you drop a small part in the hull is it will always show up in back after a ride.

If that bolt made it past the rotary valve i would be amazed. Put everything together, go for a ride with some time throwing that machine around and then look for the bolt at the rear of the hull.

 

[GT6Racer]

I will certainly look for it, and have some peace of mind when I find it ! We’re down for a short while to fix a corroded/leaking exhaust plug..