Over revving at wot

[andrewterri]

I have a 95 SPX that I took out today to test and it sounds like it is bouncing off the rev limiter at wot. Would this be due to a wear ring/impeller needing to be changed? I got that seadoo and a 95 GTX on a double trailer a couple months ago so I do not know any history. I am replacing the grey lines on both skis. On the SPX I put a new main line and filter on before testing. Old lines were oozing out the normal green stuff so a rebuild on the carb is coming next. I just wanted to make sure it would run in the water before putting to much money in them. Ski ran great other than a slight hesitation from a dirty carb. I keep the ski at 3/4 throttle so I would not damage anything with the engine bouncing on the limiter.

Thank you in advance for your help

 

[Spxxx]

My 97 SPX does the exact same thing. I can't go over 3/4 throttle as it bounces off the redline, also does hesitate when taking off.

 

[andrewterri]

Ya it hesitates for a second when you take off. What did you do about yours over revving Spxxx? Is this just normal with this model?

 

[Spxxx]

Ya it hesitates for a second when you take off. What did you do about yours over revving Spxxx? Is this just normal with this model?

I know for a fact it isn't normal. I haven't done anything yet since I don't really know what the issue is. I just ordered a new wear ring however and I'm going to see if that helps. Whatever the issue is it's likely the same for the both of us though. Take some pics of your impeller front and back and let me know what you see also.

 

[andrewterri]

Ya I will. I think it would be the wear ring. my thoughts are that the proper pump pressure is not being reached which is allowing the engine to over revv. I am going back to the lake tomorrow with the wife to cruise around and we will just keep it at 3/4 throttle. how long have you been doing that? any problems running at 3/4 that you know of

 

[Spxxx]

Ya I will. I think it would be the wear ring. my thoughts are that the proper pump pressure is not being reached which is allowing the engine to over revv. I am going back to the lake tomorrow with the wife to cruise around and we will just keep it at 3/4 throttle. how long have you been doing that? any problems running at 3/4 that you know of

I just got the ski a couple months ago and it has done it since I first took it out. Other than bogging at take off and hitting redline it runs very well.

 

[Matt Braley]

If a damaged wear ring is not propelling the ski correctly then it's not cooling the ski correctly either. Also check the seal/carrier or carbon ring to make sure it's not leaking. If it does leak at all then it draws air in that creates the cavitation. The pump has to be sealed to the hull well or it will leak air in there also.

It's also possible that a previous owner installed the wrong impeller. They are pitched specifically for each ski but so many people just run whatever is laying around or buy one off ebay when neither they or the seller has a clue.

 

[eavega]

I posted this video back in October of my 95 SPX that I had just gotten running.
[video=youtube;sGobhpe-aBc]https://www.youtube.com/watch?v=sGobhpe-aBc[/video]
I was concerned that the motor noise was not consistent at WOT (you can clearly hear it at 0:36 - 0:45). I was told by the responses that it was bouncing off the rev limiter most likely from the wear ring. When I checked it out, it was way out of tolerance (like almost 1/4" gap!). I changed out the wear ring over the winter and now the clearance is as expected, but have not tested it on the water yet. I'm hoping to get it out on the water next week.

-E

 

[andrewterri]

Eavega, mine does the same exact thing. It also makes the same sound from a wide open hole shot. And when try to do a donut.

 

[Spxxx]

Eavega, mine does the same exact thing. It also makes the same sound from a wide open hole shot. And when try to do a donut.

I can confirm my also hits redline at takeoff or spinning donuts, only at full throttle though.

 

[1983]

you all are cavitating

 

[Spxxx]

you all are cavitating

Most common issues that cause this?

 

[1983]

wear ring worn out, gap too large between impeller blades and ID of wear ring.

carbon seal leaking, aged, cracked, worn. ( i dont run carbon on any of my skis, i convert to bearing race setup, a brand new one, and 1 pump of grease into zerk after each ride, it will never lock up, people just used to neglect them )

debris in intake grate/jet pump causing restrictions of water flow.

neoprene seal missing or damaged allowing air into pump stream and disrupting thrust thus causing cavitation.

 

[1983]

impeller blades, bent, damaged, nicked, etc.

 

[Spxxx]

impeller blades, bent, damaged, nicked, etc.

You mean something like this ?

http://imgur.com/ZV79z3f

 

[Matt Braley]

Most common issues that cause this?

If a damaged wear ring is not propelling the ski correctly then it's not cooling the ski correctly either. Also check the seal/carrier or carbon ring to make sure it's not leaking. If it does leak at all then it draws air in that creates the cavitation. The pump has to be sealed to the hull well or it will leak air in there also.

It's also possible that a previous owner installed the wrong impeller. They are pitched specifically for each ski but so many people just run whatever is laying around or buy one off ebay when neither they or the seller has a clue.

 

[1983]

yes, those nicks dont help, but i would like to see more pictures of the wear ring, gap between blades and wear ring cant be too much or it will cavitate, also the impeller boot is broken and chunks missing, that doesnt help either but can be replaced easy when you do the wear ring

You mean something like this ?

http://imgur.com/ZV79z3f

 

[mikidymac]

From the picture it looks like there is a large gap between the impeller and housing. It also almost looks like the white is showing from the fiberglass backing of the wear ring. Is the rubber lining gone?

 

[andrewterri]

I think this is my problem. I will get a new wear ring ordered and check the carbon seal.

 

[AdamXP800]

wear ring worn out, gap too large between impeller blades and ID of wear ring.

carbon seal leaking, aged, cracked, worn. ( i dont run carbon on any of my skis, i convert to bearing race setup, a brand new one, and 1 pump of grease into zerk after each ride, it will never lock up, people just used to neglect them )

debris in intake grate/jet pump causing restrictions of water flow.

neoprene seal missing or damaged allowing air into pump stream and disrupting thrust thus causing cavitation.

Doesn't the 95 use the carrier bearing

 

[1983]

probably does use carrier, but i put it on all my skis regardless of what it had oem, i cant stand carbon ring setup. i get the upgraded new one from osdparts.com for 95 xp.

has dual lip seal, grease it after each ride and go!


Rob

 

[Spxxx]

From the picture it looks like there is a large gap between the impeller and housing. It also almost looks like the white is showing from the fiberglass backing of the wear ring. Is the rubber lining gone?

I'm not too sure but it is definitely worn out. I ordered a new one and will let you guys look over the pictures when I tear the pump down, I'd like to hear your opinion.

 

[eavega]

Eavega, mine does the same exact thing. It also makes the same sound from a wide open hole shot. And when try to do a donut.

So, I finally got my ski on the water after installing the new wear ring. The odd pulsating sound is gone, no cavitation. New wear ring solved that problem completely. The ski is hitting 47 MPH by GPS, which is the expected WOT speed for this machine!

Rgds

Eric

 

[1983]

NIce man! Get some hours on it this season

So, I finally got my ski on the water after installing the new wear ring. The odd pulsating sound is gone, no cavitation. New wear ring solved that problem completely. The ski is hitting 47 MPH by GPS, which is the expected WOT speed for this machine!

Rgds

Eric