Can't remove impeller

[Guest_User]

What do you mean by "clearance in the pumps?" The gauge needle was a little over 7000, so if I had to guess I'd say I hit the limiter at 7200. I have it on video, I'll go double check.

I have seen this to.
I wonder how accurate 14 year old tachs really are.
I guess with an inductive test tach, or something like a Tiny Tach that has max rpm in memory would confirm max rpms.

you also getting good speeds. I would think speed would suffer if the clearance was to much...
I wish I had those rpms, but the way I figure max torque is @ 6250, and the boat seems to cruise really well around there...

My speedo is also off 5-6 mph... nice speeds you have there!

Video, cool!, can ya post it?

I like to read success stories! :thumbsup:

 

[dbracela]

It's on the iPhone, if I can figure it out I'll post it.

If Dr.Honda meant wear ring to impeller clearance then it's very tight, as in I was worried they were gong to get chewed up tight. Like I was saying earlier I cruise at half to 3/4 throttle which I imagine is around what you are referring to. There is so little difference in speed from 6500 rpm to 7200 that it seems pointless to keep it pinned and push them that hard.

When I took the old wear ring out, all I had to do was remove small set screws the previous owner had installed and it fell right out. It was tougher getting the new one into the right side. When I got the new pump for the left side I had to cut
the ring out and it was near impossible to get the new one in. The left side clearance is slightly less then the right as it sits right now. Now that I'm getting curious about it I better go and see if I cut into the new ring at all.

 

[Guest_User]

.
. There is so little difference in speed from 6500 rpm to 7200 that it seems pointless to keep it pinned and push them that hard.

I agree, I`ve spent so much time and coin on the boat, no reason to kill it, and it is 14 years old...
I think the slight increase in speed you have compared to mine is the additional degree of pitch. Good nonetheless! Thanks...

 

[dbracela]

My neighbdour's must love me... Was just out in the driveway to check the clearance. Let's just say its tight, really tight. I did notice a little spot of rust on the right impeller...crazy. Glad I went out there though. I always flush at the lake cause it's easier for me. But I did take some dirt roads home and man was it caked in there. So of course I had to lie under my boat at 2300 hours using my phone as a light to spray it out and throw some anti-corrosive spray on em.

As for time and money, I hear that. I have been restoring a '67 mustang from the ground up and the boat has it beat in terms of cost, or at least pretty damn close.

As for the speed, I'll update when I have a full load of people and the dog!!

 

[Dr Honda]

I think you guys have the clearance taken care of. I was referring to the gap between the wear ring and impellers. When it starts to open... it normally shows up as higher top RPM's. (before cavitation happens)

I was just surprised that with the 24 degree trail pitch, you are getting up to 7200 while running. BUT... that is an indication that your engines are healthy.

As far as the tach's being wrong... that is a possibility, but I would have a hard time thinking both drifted the same amount.

 

[dbracela]

Dave from Impros just emailed me back, he was curious to see how things went on his recommendation. I told him things seem fine but haven't tried pulling up a skier and that I'd keep him posted. He is willing to help if there are issues so that's a bit of a relief. I think I read somewhere that these things can be re-pitched?

Dr, should I be expecting the cavitation to return soon if that is why I am able to reach max RPM?

 

[cdnjaguar]

That's awesome!! I'm glad you are happy with the new impellers. Did you modify your engines at all? Just referencing the application chart and the 16-24 is recommended for the challenger 800 with a modded engine. 16-22 for stock.... Starting to wonder if I could have got away with 16-24, now.

 

[Dr Honda]

Dr, should I be expecting the cavitation to return soon if that is why I am able to reach max RPM?

Not necessarily. Since you changed the impellers... we don't have a real baseline to go by. If you start touching your rev-limiter... we will have to address that later.

But... I'm glad Impros got back to you about it.

 

[dbracela]

That's awesome!! I'm glad you are happy with the new impellers. Did you modify your engines at all? Just referencing the application chart and the 16-24 is recommended for the challenger 800 with a modded engine. 16-22 for stock.... Starting to wonder if I could have got away with 16-24, now.

Hey, no I haven't modified the engines. If you look higher in the thread you will see that Dr. Honda and I were discussing possible problems with the pitch that impros recommended for the Skats. The app chart actually shows 17/22's for my boat and the concern was with the higher exit pitch that impros sold me on might cause the engines to bog down. That didn't happen yesterday, mind you I was only driving around for an hour or so. I did lose a little top end speed. I did notice that at low speed in the no wake zone I had as slight hesitation that I didn't have before, but I also haven't changed the plugs, etc, for a while, and the boat sat for a few weeks after a disaster of a weekend.

Also, the rev's were hitting their max, and after a talk with Doc and a little googling there may be something wrong going on. I will post more of my experience with the impellers when I have had the boat out for a full day of skiing and towing the tube.

I wish I could give a direct comparisson between the stock impellers (which looked suspiciously like skats but marked with an OEM part number), and the new 16/24 swirls... but I had such bad cavitation on the right side before the swap that the comparisson wouldn't be a fair one. I changed one pump, both wear rings, carbon seals, SS ring and O-rings, accordion boots, pto boots, neoprene seals, sealed the shoes as best I could, repaired the damaged tunnel... so it's hard for me to say what cured the cavitation. I believe it was the carbon ring asssembly based on other posts and some conversations I've had with the smarter guys on here.

What boat do you have, I'd like to see what the chart I have been looking at recommends.

 

[dbracela]

Not necessarily. Since you changed the impellers... we don't have a real baseline to go by. If you start touching your rev-limiter... we will have to address that later.

But... I'm glad Impros got back to you about it.

I was kinda wishing you'd say "nah Dan, everything is perfect..." haha


Yeah, he was good about it, quite apologetic for taking so long to get back to me, seems he had a bad few days. He's actually going to look into it even though things seem ok and get back to me again.

 

[dbracela]

I ask too many questions... How will I know if it starts to hit the rev limiter, will it bounce? Or do you mean it will reach 7200 and not go any farther?

 

[cdnjaguar]

Thought not, just wanted to check to make sure I wasn't missing another thread or anything Shouldn't the 24 exit pitch maintained your top end?

I have a 1998 Speedster.... this is the chart I have been going off of:

http://www.skat-trak.com/pdf/ImpellerApplChart_2011_SeaD.pdf

Called Skat Trak tech support on Wednesday and he spec'd out the 140-57 16-22 Swirl for my boat, which I thought odd as I come to believe that the stock pitch is 16-25 (I could be wrong).... He said the chart should have been updated in the Chart as it just lists N/A's right now. I'm replacing both impellers, the stock ones are dinged up with some material missing. I will let you know how much of a difference it makes in a few weeks when they get delivered and on the boat.

 

[Guest_User]

Thought not, just wanted to check to make sure I wasn't missing another thread or anything Shouldn't the 24 exit pitch maintained your top end?

I have a 1998 Speedster.... this is the chart I have been going off of:

http://www.skat-trak.com/pdf/ImpellerApplChart_2011_SeaD.pdf

Called Skat Trak tech support on Wednesday and he spec'd out the 140-57 16-22 Swirl for my boat, which I thought odd as I come to believe that the stock pitch is 16-25 (I could be wrong).... He said the chart should have been updated in the Chart as it just lists N/A's right now. I'm replacing both impellers, the stock ones are dinged up with some material missing. I will let you know how much of a difference it makes in a few weeks when they get delivered and on the boat.

looking at that chart and a few others, I`m wonder what is the differences between the 99 and 98 challengers that have different pitch impellers...
What`s weird is when purchasing parts for our 98, we received pump housing that were for 99+ that have the brass T nut inserts than the plastic encapsulated nylok nut... even tho these are current and IMHO better.

as far as the 16-25. I found one link in a German jet ski parts place (google) that said that after looking thru many many search options. which is also strange that BRP lists some impeller pitch numbers for some years and not others in the Shop service manuals...

 

[Dr Honda]

I ask too many questions... How will I know if it starts to hit the rev limiter, will it bounce? Or do you mean it will reach 7200 and not go any farther?

You will hear it. Basically... the CDI/MPEM will start to cut the ignition. So... it will sound like a high speed miss. BUT... this will only become an issue if you are holding it WOT all the time. The temporary solution is to just pull the throttle back a little.

Thought not, just wanted to check to make sure I wasn't missing another thread or anything Shouldn't the 24 exit pitch maintained your top end?

I have a 1998 Speedster.... this is the chart I have been going off of:

http://www.skat-trak.com/pdf/ImpellerApplChart_2011_SeaD.pdf

Called Skat Trak tech support on Wednesday and he spec'd out the 140-57 16-22 Swirl for my boat, which I thought odd as I come to believe that the stock pitch is 16-25 (I could be wrong).... He said the chart should have been updated in the Chart as it just lists N/A's right now. I'm replacing both impellers, the stock ones are dinged up with some material missing. I will let you know how much of a difference it makes in a few weeks when they get delivered and on the boat.

You can't compare the pitch of one manufacture's impeller to the other. When they measure pitch... it's at the outer edge of the blade. BUT... the people who make them, only make so many impellers. SO... if the original hub was a straight 20 degree pitch... and they re-pitch to a 17-22... that means that the "Root" of the blade isn't pushing the same as if the original hub was a 21. Also... some companies have a fatter, or thinner hub (that's why Solas work better for top speed, and fuel economy) OR..... there could be more blade overlap. (That's why Swirls work so well to fight cavitation)


Finally... unlike a prop... the impeller is also influenced by the size of the pump nozzle. Since we are building pressure behind the nozzle... different impellers will load differently regardless of pitch.

 

[cdnjaguar]

It's starting to make sense now, than you for the info Tony!