Seadoo 720

[Rolfe]

Hi people can anyone please help me ? I have a seadoo 720 and my rotary valve was in 2 pieces. I have a new rotary valve timed it up,, BUT the spline it sits on has play in it, only back and forth not up and down side to side etc if that makes sense. So if I hold the spline and spin the drive shaft the way of drive I can hold the spline still and it makes a clicking noise is this right ? But if I put mole grips on the spline and turn it to the direction of drive there's no slip and it drives the shaft. Any help is much appreciated.

 

[Rolfe]

Hi people can anyone please help me ? I have a seadoo 720 and my rotary valve was in 2 pieces. I have a new rotary valve timed it up,, BUT the spline it sits on has play in it, only back and forth not up and down side to side etc if that makes sense. So if I hold the spline and spin the drive shaft the way of drive I can hold the spline still and it makes a clicking noise is this right ? But if I put mole grips on the spline and turn it to the direction of drive there's no slip and it drives the shaft. Any help is much appreciated.

Is there anyone that could please help me on this it really will be very appreciated?!

 

[benjilafouine]

I thought the administrators of the forum would have picked this: you are posting in the wrong forum. This is the 4 stroke forum and you have a 2 stroke.

Maybe @mikidymac will pick this one up as he is a pro on these old models (plenty of other guys too).

 

[mikidymac]

I thought the administrators of the forum would have picked this: you are posting in the wrong forum. This is the 4 stroke forum and you have a 2 stroke.

Maybe @mikidymac will pick this one up as he is a pro on these old models (plenty of other guys too).

Sorry, I was actually out riding my skis this weekend for a change, LOL.
Just busting your chops Benji.

 

[mikidymac]

Sure sounds like you have a stripped rotary gear.

So if you hold the rotary shaft you can turn the engine over but the shaft doesn't spin?

 

[benjilafouine]

@mikidymac I always keep an eye on my computer every day...

 

[Rolfe]

Sure sounds like you have a stripped rotary gear.

So if you hold the rotary shaft you can turn the engine over but the shaft doesn't spin?

Yes that is correct, I have been you tubing some videos but I wasn't 100% and have seen the brass rotary gear is the one that has failed ? I have just brought another ski for the sun whilst I still have it lol and am going to take the engine out of my seadoo in the next couple of weeks and see what the bottom end reveals But do you think my problem is that gear and roughly what would the gear cost me and where could I possibly buy one from ? I live in the uk! Also I'd just like to mention that I really appreciate the help . Many thanks, Steve.

 

[Rolfe]

Can I just say I can hold the rotary spline still and spin the drive shaft but if I turn the rotary shaft it will turn the drive shaft but slips. Thanks,Steve

 

[mikidymac]

It's the brass gear then.

You need to take the engine apart and clean it all out and install a new rotary shaft.

There is a good shaft it bent the shaft when the gear got chewed up.

I know SBT sells complete shafts but not sure about shipping to the UK.

 

[Rolfe]

Ok brilliant. Yes I will strip the engine and see what I uncover. I will check the crank, hopefully the crank is ok, if this is ok I will rebuild the whole engine and get it ready for next season.

 

[benjilafouine]

So you have a second ski while the first one is on the fritz? I did that last year. It is too painful not having a ski to ride in the midst of the summer and when it is going to take a month to fix it ! Been there in 2015.

 

[Rolfe]

So you have a second ski while the first one is on the fritz? I did that last year. It is too painful not having a ski to ride in the midst of the summer and when it is going to take a month to fix it ! Been there in 2015.

Yep, just brought a Yamaha wave raider 700, nothing fancy but still great fun, mind you saying that my seadoo isn't the greatest ski but never the less still great fun. The seadoo is probably going to take longer than a month, I live in the uk so it's not as easy to get hold of the parts.