Rotary Valve issue.

[hess996]

Ok long story story I have been doing a rebuild/customizing on my 1996 seadoo speedster with the twin 717. I kinda had a goal that even though I have never done anything like this before, I wanted to try doing it solo just by doing some good old fashion research. I have the full top end rebuilt and is all perfect in factory spec. The crank all looked good as far as wear and tear and factory check specs, so i left that, the rotary valve, pto and flywheel alone. I decided im going to premix. Pulled the oil tank lines etc and began to pull the oil pump out. Since I had to pull the rotary valve cover off to remove the gear on the pump i find what seems to me to be a major problem. The rotary valve cover, rotary valve and the engine block its self have major scoring. replacing the cover and valve is no problem. My question is what can I do about the damage on the block? Right on the edge of the ports has some good sized dings. Any help or direction will be very much appreciated. At this point I have around 600+ hrs in a 6 month time frame invested, so if there is anything I can do to properly fix this I will. Honestly as much as I don't want to rip the motors apart again I'm wondering where its this far if I should just go all in and get a replacement bottom end with new cases, crank, bearing, rotary valve shaft, pto and flywheel. That is if anyone makes a bottom end kit. I'm going to try to post pics to help a little more in seeing the issue. I just don't know how major or not this is. I will be doing a full post with all the info from start to finish when I get this issue fixed. Its the last thing till it all goes back in. Thanks again,



























and the motors just for fun haha. Minus they dont have the blue intakes on in these pics.








Justin

 

[Dr Honda]

Looks nice.


OK... the RV. How deep is the gouge in the engine case? If it's superficial... put in a new valve, and go have fun. If it's deep... then the case needs machined clean.


Now... before you get too deep... you do realize that the RV gears need oil from your oil tank... Right?? I would recommend leaving the tank in, and leave a quart or so in it, just to keep the RV gears wet.

 

[hess996]

I did find out about the RV gears and oil after. Since oil tank and lines are out already and I have other plans for that space. I was hoping I could fab up a smaller one and just run feed and return lines? I just really am liking that cleaned up look. This is killing me.... So close to hear them for the first time!

Looks nice.


OK... the RV. How deep is the gouge in the engine case? If it's superficial... put in a new valve, and go have fun. If it's deep... then the case needs machined clean.


Now... before you get too deep... you do realize that the RV gears need oil from your oil tank... Right?? I would recommend leaving the tank in, and leave a quart or so in it, just to keep the RV gears wet.

 

[ocod]

Looks Fantastic!

Wait till racer sees this!
He may just jizzle

 

[Dr Honda]

I did find out about the RV gears and oil after. Since oil tank and lines are out already and I have other plans for that space. I was hoping I could fab up a smaller one and just run feed and return lines? I just really am liking that cleaned up look. This is killing me.... So close to hear them for the first time!

You can like the clean look all you want... but you have to feed the engine oil. (sorry)


BUT... now that I look at your pics again... the valve that has damaged... I'm seeing disturbing rust. I'm seeing rust on the shaft, and a distinct rust line on the cover. SO... you may want to check the crank for rust too.

With that said... if you have any rust on the RV shaft... that seal will wear out quickly, and the engine won't hold oil in the center gears. I just put 2 new engines in a boat because the oil tank was (more or less) draining into the engines via the RV.


I'm not trying to be harsh... but I would hate to see you do all that work, and have problems.

 

[hess996]

Sorry this may sound dumb but like I said this is a first time thing and all. So I cant even do the block off plates and run premix and I have to keep the pumps on the motors to feed the RV shafts? This is why I didnt have any of my friends come over. I get told to change something away from stock and bad things happen haha.+-

You can like the clean look all you want... but you have to feed the engine oil. (sorry)


BUT... now that I look at your pics again... the valve that has damaged... I'm seeing disturbing rust. I'm seeing rust on the shaft, and a distinct rust line on the cover. SO... you may want to check the crank for rust too.

With that said... if you have any rust on the RV shaft... that seal will wear out quickly, and the engine won't hold oil in the center gears. I just put 2 new engines in a boat because the oil tank was (more or less) draining into the engines via the RV.


I'm not trying to be harsh... but I would hate to see you do all that work, and have problems.

 

[hess996]

honestly with all the time and work on this whole deal and like you said all this and have problems I think im just going for a full fresh bottom end. I didnt have any intention of doing them as far even as I did. Its just ever part I took off the next one and issues. So yeah common sense would say the cranks need to be replaced too. I did look as much as I could with out splitting the cases and didnt really see any problems. I have plenty of pics of them with the topends off if you want me to post to see if you see anything?

 

[Dr Honda]

You can go "Pre-mix" if you want. That's not a prob at all. But... the gears that drive the rotary valve (RV) need to have an oil bath. It doesn't pump around, or need to be under pressure... it's just a bath. If everything is absolutely perfect... you could put some oil in the gear cavity, and be done. BUT... if the seals leak (either the RV shaft, or the inner crank seals) the engine will suck out the oil, and leave the gears dry. So... Seadoo decided to simply hook up a couple hoses from the oil tank, and it keeps the gears wet. That way... if you have a small amount of weepage... the tank keeps the gears lubed.


Now... the boat I just finished...

Basically... it had 2 perfectly good, running engines. BUT... the seals in the RV were shot, and over the winter... a gallon or more of oil, from the tank, drained into the engine. Since this engine was an extreme case of bad RV seals... it would leak enough oil, overnight... that the engines wouldn't start. (hydro-locked with oil)


Anyway... that's why you need the oil tank, even of you take off the oil injection pumps.


As far as pics to look at... post anything you like... and we will look.


As I was saying... I didn't like the rust line on that damaged cover... but if the other cover was OK... you may only need a better inspection on the damaged engine.