96 Seadoo Speedster Twin 717 Wont go over 10mph! Help!

[WJKraze]

So I have a problem with my 96 Speedster. I first had a problem with idle not matching and a problem that felt like cavitation which I thought were my wear rings. I fixed the idle problem and installed new wear rings and new Nu-Jet Impellers. I tried to take her out today and it starts and idles correctly in water but when accelerating the boat refuses to go over 10mph. The boat makes a lot of wake, the engines rev smoothly and evenly but the boat does not accelerate over 10mph. What else could this be guys!? try to be descriptive with me when replying as I am handy , but not very experienced when it comes to this. Just a not a neoprene seal is not "needed" for these pumps but I put some in anyways, also I cracked the plastic driveshaft dust covers when installing the pumps, I don't see how but I did. PLEASE HELP GUYS, Thanks!

 

[Waterluvr]

So your engines are achieving WOT operation and rpm's and you have very little hull speed correct? Two things, what are the pitch number's of the Nu-Jet impellers you used, and what is the clearance from the blade tips to the new wear rings?

 

[WJKraze]

Yes you are correct, and I installed the SD-A 5.5 Impellers. I didn't have a blade style feeler gauge but they are very close to the wear rings

 

[Waterluvr]

Yes you are correct, and I installed the SD-A 5.5 Impellers. I didn't have a blade style feeler gauge but they are very close to the wear rings

Wear ring clearance is a big deal, using new BRP wear rings and a new or properly reconditioned factory impeller will result in a clearance tolerance of less then .010" in most cases. BRP says up .040 is acceptable as a wear guideline and both of those would look "really close" as you put it to the naked eye but I'd be looking for .010 or less and Nu-Jets are widely considered to be junk for having any quality control when it comes to tolerances. You could be off .080" and it would look close.

Your boat needs BRP# 271000497 impellers and they are an 11/22 pitch, throw the Nu-Jets in the scrap pile where they belong. Seriously, you're wasting time and money messing around with aftermarket crap that doesn't conform to necessary performance tolerances and specs. The Nu-Jets you used were designed for the 96HX jet ski and were never intended to run a boat hull even though they just happen to fit the pump. Get the OEM impellers for your boat, SBT has remans for 60 bucks a piece just send in your old cores to them.

Some of the other issues that can cause cavitation or not allowing the boat to get out of it's own way like you're experiencing are stripped driveshaft/pto splines, leaking ride shoes (you'll need someone with the puller to evaluate the boat for that). Also, the driveline can allow air to pass through the hull and into the pump if the bellows/carbon seal are worn and that might be part of your problem.

I'd take it all apart and start by pulling each drive shaft and making sure they are perfectly straight and all the splines are good at both ends and the pto hub splines on the engine are good. Have new rubber bumpers to replace in both ends of the shaft.

You might as well replace the entire shaft seal with new bellows, carbon seal, carrier o-rings etc while it's apart. SBT has a kit for doing all of that and it's much easier on the wallet than buying it all piece meal from BRP, I use lot's of them and they work well.

Use the correct impellers for your boat and inspect the blade tip clearance when you initially install them and while you're torquing the pumps to the ride shoe. Do whatever it takes to make sure the pumps are sealed to the face of the shoe, in your case using the neoprene seal was a good idea but it might help to apply a thin bead of silicone to the face of the shoe before the pump goes back on.

 

[hotrodssnova]

Have you checked to make sure that your buckets are fully up and not restricting the jets?

 

[grinditout]

I second that hrn.

 

[WJKraze]

So I ripped out the Nu-Jet Impellers, and put the originals back in. I also pushed the rubber boot back on the carbon ring and tightened it up so the seal would be tighter there. Lastly, I decided to put a bead of bathtub sealant around the outside of the shoe ( just to see what would happen ). Most of the carbon ring looks good, I couldn't push the boot back completely off of the ring but most of the surface looks good on both. I did all of this and went out to the water and the boat flies, gets up on plane and I was doing about 50mph at 3/4 throttle. But now I'm confused as to what fixed the problem? and is it really fixed? Also, it sounds like a bearing is bad in the pump there is some odd noises in the back that sound like a bad bearing what could that be? Any help would be awesome, thanks guys!

 

[Waterluvr]

Can you tell which side the bearing noise is coming from? You may have a leak at the pump cone, at the rpm rate the pump turns it only takes a minute to lose the oil. Did your shaft have the rubber bumper on the end when it went back together?

Best to pull the pump and see if you might have spun a bearing etc., highly recommend pressure testing the pump cone before replacing the plug and sealing it up after your that far into one. Whatever is going on there won't take much to diagnose compared to what you started with.

Congrats on getting it running right, fun aren't they?

 

[WJKraze]

Very fun, I wish I knew what fixed the problem for sure, but I'm thinking it was the impellers! Ill have to do some diagnosing it sounds like its coming from port side

 

[rgardner928]

Not to resurrect an old form but I have questions regarding this topic. How the hell do you get the rubber stoppers back into the ends of the drive shaft?

And two..I'm having the same issue. My wife and I are little fat asses and I would like to increase the pitch of my blades for more low end thrust. What would I change my 11/22 blade to?

 

[Dr Honda]

The problem with pulling an old thread is... no one who posted in this thread has log-in in a long time. SO... you wont' get an answer. Please... DO NOT post on old threads. Start your own.

To put the bumpers in... remove the shaft, and stick them in the ends.

Impellers are up to you. Skat-Trak "Swirl" impellers are you best bet for low end.