05 rxt 8000rpms but only 59mph?

[Seadoo rxdi]

I just bought a used rxt 215 with 220 hours on it. I am trying to figure out why I can only get 59mph at 8000rpms. This is with a full tank and the water was quite choppy. But i thought these things should reach 70mph roughly?

Here are some pics of the impeller and wear ring. My only guess so far is that slight bends in the impeller trailing fins could be causing it? Or could it, they look rather minor. The wear ring looks fine.

I did find that the green cone had backed off and was halfway down the driveshaft. Could this be a factor? Should I just leave it off now that I have the pump pulled off?

Am I wrong to assume this machine should do closer 70 at 8000rpms?

The impeller is a 13/18 concord.

Edit: I determined the speed from my phone GPS. Not the speedometer on the ski

 

[ski-d00]

you will need smooth water, not quite choppy, to reach 67mph which is all it should do. the speedo may read 70.

impeller boot should be in place, not removed. could have been an issue but guessing choppy water is the real problem.

 

[Seadoo rxdi]

you will need smooth water, not quite choppy, to reach 67mph which is all it should do. the speedo may read 70.

impeller boot should be in place, not removed. could have been an issue but guessing choppy water is the real problem.

Thank you for your input! I'll put it back together and try for a less windy day and see what I get. Hopefully Sunday.

Is 8000rpm about where it should be at though?

 

[ski-d00]

8100 is ideal but 8000 is pretty normal. not sure what the concord does on your ski though.

 

[waternewbie]

My 2005 rxt at 8000 does 74 and is all stock

 

[ski-d00]

My 2005 rxt at 8000 does 74 and is all stock

I think you need to get a new gps then. lol

 

[waternewbie]

I think you need to get a new gps then. lol

Maybe so, maybe so. At least it makes me feel like im going fast!

 

[Seadoo rxdi]

Ya no way I could see hitting even 70mph GPS on a stock rxt.

 

[Seadoo rxdi]

I sucked out some oil in Hope's of getting that extra 100 to 150rpm. Maybe that will give me another mph or 2.

It looks like it was very slightly above the top bend. I got sucked out somewhere around a quart and now it is sitting right in the middle of the 2 bends. I am about to take it out and will let you all know what I get!

 

[Seadoo rxdi]

Also, I don't think it matters much BUT, I do have a p0461 code. Which I'm quite certain is mpem.
It says "SENSOR" and "FUEL LO" With a full tank.

It shouldn't hurt anything to run it like this I assume? Just an occasional annoying beep.

 

[Seadoo rxdi]

Well just reporting back. I hit 60mph. But seems to be about all she gots at 8050rpm. Could be the slight impeller trailing edges being a little bent causing it.
Anyways I'll leave it be. Not worth it for an extra 2 or 3 mph.

 

[ski-d00]

That's a lot of speed lost, more like 7 or 8 mph. Something major is wrong most likely with your pump/impeller.

 

[Seadoo rxdi]

That's a lot of speed lost, more like 7 or 8 mph. Something major is wrong most likely with your pump/impeller.

I wonder if Its the impeller itself being aftermarket? Idk what the oem pitch is or what this ski will do with the oem because I got it with the concord 13/18 already installed. Could that be a factor?

 

[Seadoo rxdi]

I can't see anything else it could be other than the impeller.
-The wear ring is in great condition.
-Its turning 8050rpms, so nothing on the engine side.
-The carbon seal appears to be fine. I can barely even pull the boot back. Plus she doesn't take on water so I'm gonna assume it's fine.
-I feel no cavitation. If I pin the throttle from idle speed, she takes off pretty good in my opinion without shooting the rpms up too high.
Although I can't compare it to anything else other than my RXDI.

I feel as if this impeller is causing top speed loss.

Anyone else have experience with the concord 13/18?

 

[Seadoo rxdi]

 

[Seadoo rxdi]

Edges are a bit tweaked. I'm gonna try to use a heat gun and bend them back.

Anyone think this could be the cause of the top speed loss?

 

[mikidymac]

Don't heat the impeller or you will make it brittle.

 

[Seadoo rxdi]

Don't heat the impeller or you will make it brittle.

I found it bent fairly easy without heat so I just used a crescent wrench and some muscle. Gonna put it back together and hope I can get those few extra mph

 

[Seadoo rxdi]

After bending trailing edges back. It will be interesting if these little bends make a huge difference on top speed.
I will report back!

 

[Seadoo rxdi]

Reporting back...so I'm still hitting 60mph tops. However bending the impeller trailing edges back straight made my rpms go down to 7500 to 7600.

 

[Seadoo rxdi]

So I'm thinking I'm due for a sc rebuild. I stuck a ratchet extension through the pump and into the impeller to prevent it from spinning while I turned the sc wheel counterclockwise.
I set my torque wrench to only 50in lbs and I couldn't even get it to click without spinning the sc.

Is this a valid way of testing the sc slip?

 

[beergut]

dude- i could tell from the first pic you needed a new impeller. it doesn't take much damage to an impeller and ring to mess with performance. that impeller is junk. and I'd put a new ring in it also since it's all apart and rings are cheap. hell, i lost 10 mph just with a few nicks on my stock gtx 215 impeller- just finished rebuilding my pump. i ended up putting a stainless ring in it.

 

[Seadoo rxdi]

dude- i could tell from the first pic you needed a new impeller. it doesn't take much damage to an impeller and ring to mess with performance. that impeller is junk. and I'd put a new ring in it also since it's all apart and rings are cheap. hell, i lost 10 mph just with a few nicks on my stock gtx 215 impeller- just finished rebuilding my pump. i ended up putting a stainless ring in it.

10mph really? I'd like to see those "knicks".

What kind of top speed and rpm are you seeing on your gtx?

The impeller seems to be in good shape as does the wear ring. I've already put it all back together and back on the ski for now.

I now have the sc removed and about to tear it down and rebuild it as soon as the kit comes in.
I'm pretty sure my issue is that it has too much slip and not able to make full boost.

P.s. how do you like the stainless steel wear ring? How long have you had it? Have you sucked up any debris without major damage to it?

 

[ski-d00]

You do know that the slip minimum is 44 in-lbs, right. I've seen them under 40 and they still worked fine. Your impeller is not in good shape and needs either rebuilt or replaced. You can't just bend them back to what looks good and expect them to be fine.

 

[beergut]

10mph really? I'd like to see those "knicks".

What kind of top speed and rpm are you seeing on your gtx?

The impeller seems to be in good shape as does the wear ring. I've already put it all back together and back on the ski for now.

I now have the sc removed and about to tear it down and rebuild it as soon as the kit comes in.
I'm pretty sure my issue is that it has too much slip and not able to make full boost.

P.s. how do you like the stainless steel wear ring? How long have you had it? Have you sucked up any debris without major damage to it?

You can see the dings and jagged edges in the picture I posted. they look small but causes lots of cavitation. It doesn't take much; any amount of cavitation coming through the pump will cause serious performance issues- and ANY damage to the impeller will cause cavitation and loss in performance. i consider this impeller trash... Like mentioned above, you can't just bend the impeller back to a "close enough" shape. your impeller is trash. the price to have it reworked isn't much less than a new impeller. i picked up that polished 13/18 from SBT for $160. i didnt waste time trying to clean this impeller up. On another note, a lot of people look through the rear pump and see not much gap between the impeller and ring, but if you check behind the impeller, it's a much different story. as you can see in my pics- the front of the ring is worn way more than the back. a 1/32 gap will cause performance issues. my new impeller literally touches the new steel ring. do whatever you want- it's your ski, but this lessen will eventually end with you replacing the impeller & ring.