97 sea doo challenger 787 rotary shaft not turning!!!

[imlost]

long time reader, 1st time poster. i just rebuilt my dual carbs on the boat as i was tuning them out of the water. the motor reved up and then stopped. it tries to start but no go. as i've been reading other post i figured i better check the rotary valve and shaft as it past all other tests. after pulling the cover its got wear marks in both the cover and valve. i then pulled the plugs and turned it over to see the shaft was'nt turning. is this one of them deals i need to pull motor and just go thru it or can repairs be made why'll in boat? this has been both good and bad. good i'm learning more and more about my boat hands on and bad by just doing a carb rebuild i'm now not on the water. any and all help needed thank you!!

 

[robin savell lloyd]

If this is the original engine you may want to buy a sbt engine if your rotary shaft is not turning as engine probaly has a lot of hours on it. good luck Robin:cheers:

 

[Gunsrunner]

Membership

Hi imlost,
Make sure that the shaft is not turning, there is a brass cog that can be replaced on the shaft this could be your problem. I haven't had to fix a rotory valve yet so cant tell you if it can be done in boat, obviously try first. here is a diagram to help, if you take up premium membership the workshop manual could be avaliable to you from the forum, Karl can tell you if it is there, he will need to no what boat you have.
View attachment 354

 

[imlost]

thanks for the help!!!!!

the brass gear was bad and shaft was a little bent i think, not bad enough i could really tell easly. i bought another shaft assembled and just put it in. not real happy bout the poor example in the manual with timing the valve.

if you guys have time look at my lastest post and see if you can help me would be great......

 

[robin savell lloyd]

The only concerns I would have is what about the brass that came off the other gear? were you able to remove it all? what would it do to your seals? even if something was to hapen I do believe you will still have a good core. good luck Robin :cheers:

 

[imlost]

temp fix

temp fix tell i save up for a new motor. i used a suction pump and removed all oil and what brass i could locate. she's running great in driveway!!!! this whole thing started with a simple carb rebuild and as i was tuning carbs there was a high rev and a grind. been down hill since then!!!!! but now she's running again and carbs are driveway tune for now. take'n to river in morn to dock tune then a full run tune.

not much brass was in the case only lost part of 3 teeth. :cheers:

 

[seadoosnipe]

Great job....

Sounds like the premium membership paid off for you. I've got some pix of the rotary shaft from my spare 787. I don't think you'll need to worry about the brass shavings in your chamber. Brass is softer than any of the other metal it could possible come in contact with, so I doubt that it will cause you any problems.
When you did your carbs, you need to be careful in tuning them out of the water. You've got the manual now, read in it about revving the throttle. It warns against revving to high or WOT due to "freewheeling" the motor. Freewheeling the motor, is bad on the internal parts because there is no torque on the impeller to put resistance on the rotary shaft, crank bearins and pistons.
Your better off tuning, with the air box off, in the water with your nose into a soft bank. That's been the easiest way for me to make sure I got it right. Even when I set my idle at 3k in the driveway, when I get to the river, it idles at 2k or so....and the slow speed screws needed tuning. You can't really do that on land. So, find a nice place in the water, to spend an hour or so getting intimate, getting to know how she purrrssssssss. They like the extra care....................:cheers:

 

[imlost]

w00t, this baby is a runner!!!!

she has never ran this good not even when i bought it in 2001. i had to reset the the air mix from 1 1/4 turns to 3/4 on low speed and set high speed to 1/2 turn. takes bout 5-10sec to plain and i'm 280lb guy with my 180lb buddy.

not bad for a single 787 motor... compression is still 150, top speed per sea doo gauage 50mph, i never got over 40mph before. mind you i did rebuild the jet pump 2 yrs ago but had carb probs with a lag at start. so tired to sell and it sat for 2yrs after the guy who wanted to buy didnt come thru with the cash i took it back and started the fix up.



by the way i found an over sea motor dealer where i can get rebuilt 787's and no core needed for around 500.00 us dollars. just for the hell of it i'm guna order 1 and check it out. if it is the real deal and i'm not out 500.00 bucks i'll let mods know and might bring in a few others.:hurray:

 

[kustomkarl]

That is great news...now go have some fun this weekend...
Karl

 

[Gunsrunner]

Congrats on getting it going so well, will be interested to here about the motor as well!!!!:hurray:

 

[imlost]

will do runner

next question; where would i pick the exhaust pipe boot for my 97 challenger?

"the boot that stops water from going into the boat"

 

[seadoosnipe]

Exhaust gasket...

That's the exhaust gasket and will run you about $15.00 bucks....

Your part number for it is #274000276