Super Jet Is my Midshaft trashed? Help!

[imabadfish]

before i say what happened this is what i did. I had some sluggish bottom end issues and solved it by finding out my pulse line on the carb wasn't vacuum sealed. So i replaced the gas lines and now it rips.

I know i don't have a picture but i was riding last weekend (happy with all my new bottom end power) and after about 20 minutes my ski started to make a loud wine noise and didn't go anywhere. I thought maybe cavitation because something got stuck in my pump because it was a familiar type of noise but nothing was there.

I pulled the ski out of the water and cranked it on the trailer and it was making like a tink tink sound in the pump area I thought maybe the wear ring? I pulled off the pump and checked the prop and it spins fine but i just hand turned it... I cranked the ski with the pump out and motor (61x/61x) runs fine. I checked the compression and have 180 on both cylinders. (thinking the worst like a bad crank seal, piston or something.)

Is it possible with my new found bottom end power i jtrashed the inside of the midshaft that catches the splines on the driveshaft? its kinda difficult to take a picture since its still in my ski and i don't think i can replace it without pulling the engine...

Am i on the right track or is there something else I should be looking at?

 

[D-Roc]

ah stripped driveshaft, yes it feels like cavitation or tires spinnin. that is no good. what does your driveshaft splines look like.

 

[imabadfish]

driveshaft splines look pasasble still . I put the spline tool on there for changing out the prop and it grips fine. I was afraid it was the midshaft. Anything i can do to prevent it from happening again?

 

[D-Roc]

replace both midshaft and driveshaft with new parts and align your motor properly. if you align it, they can withstand anything with any amount of hp pushing them. misaligned and you will spin the shaft. this happened to us when we installed a TL on a ski. the added torque brought out the fact that the motor was not bang on.

 

[Freakrider]

Some have used brake cleaner on both splines and JB weld it together...makes it real tough to pull back apart...some have done this cheap route and it works but it's best to get new shafts...

 

[imabadfish]

replace both midshaft and driveshaft with new parts and align your motor properly. if you align it, they can withstand anything with any amount of hp pushing them. misaligned and you will spin the shaft. this happened to us when we installed a TL on a ski. the added torque brought out the fact that the motor was not bang on.

Thanks. I was thinking of just replacing both parts as well. I'm pretty sure I was aligned good. I followed the instructions here: http://www.x-h2o.com/threads/51928-engine-pump-shimming-questions&p=690983&viewfull=1#post690983

 

[Freakrider]

make sure you use moly grease (it's designed for load bearing/ extreme pressure) for the splines and two new o-rings inside the midshaft....

 

[Waternut]

Maybe it's just me but I have a hard time believing a 61x/61x could strip the driveshaft or midshaft splines. You said the driveshaft splines are passable. I would think if you stripped the midshaft, there would be metal shavings attached to the grease on the driveshaft along with some damage to the driveshaft itself. Have you pulled the midshaft yet or spun it by hand? The pump normally tings a bit when it's out of water. The whining noise is unusual but most likely indicates some kind of bearing going out. Could be pump or midshaft bearings but I highly doubt that you stripped the splines on the midshaft AND fried the bearings unless the pump was completely seized which it isn't since you spun it by hand.

If I were you, I'd make absolutely sure of what the problem is before you start replacing parts.

 

[imabadfish]

Maybe it's just me but I have a hard time believing a 61x/61x could strip the driveshaft or midshaft splines. You said the driveshaft splines are passable. I would think if you stripped the midshaft, there would be metal shavings attached to the grease on the driveshaft along with some damage to the driveshaft itself. Have you pulled the midshaft yet or spun it by hand? The pump normally tings a bit when it's out of water. The whining noise is unusual but most likely indicates some kind of bearing going out. Could be pump or midshaft bearings but I highly doubt that you stripped the splines on the midshaft AND fried the bearings unless the pump was completely seized which it isn't since you spun it by hand.

If I were you, I'd make absolutely sure of what the problem is before you start replacing parts.

My 61x was stock last summer. I added an ada head, blackjack carb. I know its not great but it feels like so much more power than last year. Maybe I already had a problem that just got worse.

I can spin the midshaft by hand without any issues with the spark plugs out, pump out. I had the driveshaft pressed into a new vein section that is tapped for dual cooling at a local boat shop not too long ago. If the bearings were bad there, I would think they would tell me to get more money out of me. The driveshaft spines fine.

I really don't want to replace the midshaft. I pulled the intake grate out, put the pump in and when I turn the driveshaft in the intake area by hand the midshaft doesn't seem to spin.

 

[Freakrider]

the splines wear pretty equal on both shafts...if your driveshaft is fine your midshaft would be similiar in wear...if a worn out midshaft was installed, then it would ruin the driveshaft splines...you better check this out more.

 

[imabadfish]

the splines wear pretty equal on both shafts...if your driveshaft is fine your midshaft would be similiar in wear...if a worn out midshaft was installed, then it would ruin the driveshaft splines...

hrrrm. back to the drawing board then i'll mess with it some more. Anyway to test if bearings are bad?

 

[Freakrider]

hrrrm. back to the drawing board then i'll mess with it some more. Anyway to test if bearings are bad?

you have to pull motor forward and feel if it spins smooth by itself with pump out...btw few people know the midshaft bearings can be cleaned and re-packed w/ new grease by removing bearing black covers which snap back in...you would need a press...jetmaniac has $39 rebuild kits w/ bearing/3 seals also....

 

[227]

......... I pulled the intake grate out, put the pump in and when I turn the driveshaft in the intake area by hand the midshaft doesn't seem to spin.

Dude you just answered your own question. If you can spin the drive shaft by hand and the mid shaft doesn't move its stripped. Bad bearings make noise, they don't prevent the shafts from linking up and spinning. I stripped a mid shaft with my stock motor before. I tried to fix it the cheapo way by just replacing the mid shaft and keeping the passable drive shaft. ended up stripping the new mid shaft. Do it right the first time, replace BOTH the drive shaft and the mid shaft.

 

[imabadfish]

Dude you just answered your own question. If you can spin the drive shaft by hand and the mid shaft doesn't move its stripped. Bad bearings make noise, they don't prevent the shafts from linking up and spinning. I stripped a mid shaft with my stock motor before. I tried to fix it the cheapo way by just replacing the mid shaft and keeping the passable drive shaft. ended up stripping the new mid shaft. Do it right the first time, replace BOTH the drive shaft and the mid shaft.

thanks. its just hard to look up in the midshaft (even with a flashlight) while its in the ski to see if in fact its stripped out.

 

[Freakrider]

I find it hard to believe it is so stripped that it will not turn the midshaft without any load on it...

you said "The driveshaft spines fine."

is this spins or typo splines ?

 

[227]

Check out both of these drive shafts that appear to be passable, they are BOTH BAD


This one is GOOD, see the difference?


REMEMBER, if the drive shafts trashed SO is the midshaft

Note* To view press CTRL while you click on the pics

 

[imabadfish]

Crap thanks for the pics. My driveshaft looks like the first pic.

 

[JetManiac]

Crap thanks for the pics. My driveshaft looks like the first pic.

Some very good advice in this post, but another important point is spline engagement/overlap. When you first install your midshaft with new grease, pull it back off and check the grease trail for spline overlap. The first picture shows a spline underlap by about 1/2". You can also see that only 1 oring is riding on the driveshaft.

 

[kevbo]

Another big killer of splines is sand. It sticks to the grease that gets slung inside the shaft tunnel. When the pump is pulled and reinstalled it gets pushed inside the midshaft. You must pull the midshaft and clean everything including the shaft tunnel to make one last. Who does all that? Splines either last forever with very little wear of fail very quicky.

 

[Tim Loughmiller]

Some have used brake cleaner on both splines and JB weld it together...makes it real tough to pull back apart...some have done this cheap route and it works but it's best to get new shafts...

Can you explain the procedure?? I know this is a old post but Ive got a bet with a buddy that I can get this thing running before Friday (been sitting in woods since 97) 96blaster 701