impeller and pump condition gsx rfi

[jammin777]

hi guys, please view the pictures and let me know what you think. what you are looking for on the pump is one of the stater veins that has a small piece broken off. you can see the vein at the hub is curved and not straight across like the others.
also it is the side that faces the prop.
any chance of it being an issue? the impeller has a few small nicks and i think it should be ok. let me know if otherwise as i want 100 % efficienty. my main worry is the pump though. as you know, impeller exchange is cheap from sbt.
after reading the part number it is a factory impeller.
the wear ring is good 14 thousands clearance and with only a few hair line scratches.

and finally, i plan on pressure testing the pump, Ive read that you can use a mikuni pop off pressure tester but where can i get a screw in fitting for the cone filler that hooks up the the tester? and would a vacuum tester pump produce the same results? would i need to fill it with oil first for testing? thanks.

 

[Mekanix]

Think your going to need to clean up the edges on the prop, maybe send it to IMPROS to have it redone or go sbt for the same price.

Not sure what effect the damaged pump housing fin would have..

You can get a barb fitting that fits into the cone where you would normally fill it from, Just bring the plug or your cone to a hardware store and find something with the same size and thread and then you can use the pump to test.

 

[Sportster-2001-951C-Stock]

Why did you take it all apart?????

Stator looks fine to me, assuming it's a brass pump. I believe the rule of thumb is anything missing larger than a dime is going to have an effect. Some guys like to file them sharp, but it weakens them, IMO, so just clean up any casting flash if you want to get maybe another 10 RPM!

Take your cone plug with you to the H/W store and buy a fitting with the same threads, rig it up to your pop-off pump. 10psi/10min

I do both pressure and vacuum test on stern drives that I find water inside of or when I replace prop/shifter seals, before filling with oil. Sometimes a seal will only leak in one direction and stern drives are mucho $$$$.$$

 

[Mekanix]

Vacuum? Great, why didn't I think of that at the time. Now I have to pull my pump off again I didn't think of of that at the time, only did a pressure test

 

[jammin777]

lol! i took at all apart because i'm pulling the engine to have it rebuilt. I figured i would make sure all is well while it's out.
it is a plastic pump. the bearings look good so i will replace both the shaft and cone seals. what do you thank of the impeller? the nicks are only toward the top but looks great where it rides along side of the wear ring. or is that what you meant by cleaning up the casting flash?

 

[Mekanix]

The brass pump has a lot of little casting flaw's (bumps) that you can clean up a bit, but if yours is plastic then there wouldn't be that to clean up.

 

[jammin777]

dang! what to believe? i was just on impros web sight under jet pump repair and stated that a chunk missing on a stater vain even a half size of a dime could cause major performance and cavitation issues!

 

[Sportster-2001-951C-Stock]

Well, if those veins are plastic then I'd only worry about it if the veins were cracked, mainly b/c the veins provide support for the impeller bearing housing.

On the impeller, I'd just put my largest stone in my dremel and brind off any burrs, don't try feathering back to a rounded edge, nobody will see it anyway, unless they crawl underneath!

Most important is the leading edges aren't folded over (mushroomed) and the wear ring clearance is nice and tight.

 

[Sportster-2001-951C-Stock]

dang! what to believe? i was just on impros web sight under jet pump repair and stated that a chunk missing on a stater vain even a half size of a dime could cause major performance and cavitation issues!

Okay, that's what I meant!

Ask mechanix about his new impeller he said was like night and day.

My impeller looks about like yours but recently I had a rock get stuck between the trailing edge and stator vein and bent the trailing edge, I lost some top speed I think but boat still cruises just as well, IMO. I saw 45mph just before the rock went thru and now I only see ~42mph (on my dreamometer)

 

[Mekanix]

Yeah it was a big difference.

I'm guessing with the pump in that condition you may have gotten a little cavitation and were able to hit the rev limiter easily while taking off or just jumping some small waves, or just playing around and taking off again after a 360 spin....

Well mine with the stock impeller could hit 7000 from a stand still and hold it as long as I wanted to, I mean it was like on and off. If I got on plane first and then hit it, it would take off and go pretty well without feeling like it was slipping but with every wave it would spin right up.

with a Solas SD-CD 15/23 it would jump out of the water and feel like the engine was loaded down and doing useful work instead of slipping. Also coming out of a spin I could get up on plane and hit waves without "loosing traction".

Biggest difference was cruising around mid range and then hitting the gas on and off. It would jump out of the water and then bunny hop every time I hit the gas.

 

[jammin777]

cool! no cracks so should be good to go. now i'm trying to think of a way to make my own pressure gauge as i only need it for the pump cone. no carbs lol! seems that there's gotta be a way to convert a vac pump (which i already have) to a pressure pump. any thoughts?
i'll have to bring it home from work and have a look see. thanks!

 

[jammin777]

Yeah it was a big difference.

I'm guessing with the pump in that condition you may have gotten a little cavitation and were able to hit the rev limiter easily while taking off or just jumping some small waves, or just playing around and taking off again after a 360 spin....

Well mine with the stock impeller could hit 7000 from a stand still and hold it as long as I wanted to, I mean it was like on and off. If I got on plane first and then hit it, it would take off and go pretty well without feeling like it was slipping but with every wave it would spin right up.

with a Solas SD-CD 15/23 it would jump out of the water and feel like the engine was loaded down and doing useful work instead of slipping. Also coming out of a spin I could get up on plane and hit waves without "loosing traction".

Biggest difference was cruising around mid range and then hitting the gas on and off. It would jump out of the water and then bunny hop every time I hit the gas.

thats great news on the concord! any top speed or loss concord vs stock? this has me thinking lol!
oh btw, i never rode my ski yet as i just bought it cheap as a project for the winter. looking forward to next season for sure.

 

[Mekanix]

Top speed claimed to increase by 1-2mph, but I'm usually going crazy with spins and jumps rather than at top speed so I can't say for sure, It didn't really feel like it changed the top end, Just got there sooner.

 

[Sportster-2001-951C-Stock]

cool! no cracks so should be good to go. now i'm trying to think of a way to make my own pressure gauge as i only need it for the pump cone. no carbs lol! seems that there's gotta be a way to convert a vac pump (which i already have) to a pressure pump. any thoughts?
i'll have to bring it home from work and have a look see. thanks!

I think it's going to be tough trying to convert a vac pump over to pressure pump, I bet your vac pump is one of those mity-vac pumps and that will work great for testing for inward leaks but a bicycle pump would work fine to get 10psi for a pressure check. You'll need a gauge on the line to measure, a 0~60 psi gauge should work okay, or 0~30 psi is better if you can find one.

 

[Sportster-2001-951C-Stock]

Top speed claimed to increase by 1-2mph, but I'm usually going crazy with spins and jumps rather than at top speed so I can't say for sure, It didn't really feel like it changed the top end, Just got there sooner.

So you got a much better hook-up, but do you think it was impeller, carbon seal, or wear ring? Seems like you're pretty sure it was the impeller.

 

[Mekanix]

The original wear ring was scratched up but now that I look at it, I don't think it was as bad as what other people have had and still had good performance. The carbon seal was not as tight as it should have been,
I think it was the prop that made the biggest difference because of the design of it.
The stock one seems like it would chop the water coming in and not really slice into and pull it in smoothly. So any break in the flow would cause a big slip and take longer to pickup.

The concord's leading edges seem like they would slice into the water and pull it through much more efficiently, As in it would prime itself better.

 

[jammin777]

Top speed claimed to increase by 1-2mph, but I'm usually going crazy with spins and jumps rather than at top speed so I can't say for sure, It didn't really feel like it changed the top end, Just got there sooner.

yep i ride like that too but also like the rush of top speed every now and again. sooo it looks like a concord is the way to go.
now i just need to finish pulling the engine so i can send it to ses, then pull the tanks, clean the bilge flip it upside down to do some minor gel coat repair and polish. the po beached it! the top half of the hull is excellent! will probably start a simi restore thread once i really get going.

 

[Mekanix]

Well I had mine out today with a new wear ring, old prop, tight carbon seal and it was exactly the way it was before changing the prop so i'm 100% convinced its the prop that makes the difference. It could hit the rev limiter easily just by bouncing a few inches out of the water. It was like 5000-7000 jump all day long, The solas definitly stops that and only hits the rev limiter when i'm completely in the air

 

[Sportster-2001-951C-Stock]

Well I had mine out today with a new wear ring, old prop, tight carbon seal and it was exactly the way it was before changing the prop so i'm 100% convinced its the prop that makes the difference. It could hit the rev limiter easily just by bouncing a few inches out of the water. It was like 5000-7000 jump all day long, The solas definitly stops that and only hits the rev limiter when i'm completely in the air

So it's b/c the leading edges on the solas are curved as opposed to straight leading edges on the OEM prop then, it sounds like. Also blade overlap is another factor that limits the amount of progressive pitch that can be hammered into the blades.

This reminds me of the old 2 blade outboard racing props that were superior b/c they could better tolerate ventilation.

Here's a good article on how to select boat propellers:
http://www.reynoldsracingmarine.com/proptech.htm

 

[jammin777]

Well I had mine out today with a new wear ring, old prop, tight carbon seal and it was exactly the way it was before changing the prop so i'm 100% convinced its the prop that makes the difference. It could hit the rev limiter easily just by bouncing a few inches out of the water. It was like 5000-7000 jump all day long, The solas definitly stops that and only hits the rev limiter when i'm completely in the air

thanks for conforming! that is just the comparison i was hoping to read. did you note the top speed difference if any?

 

[Mekanix]

My solas prop should be back in a couple of days.

I was out for a few hours today with the stock one and got a good high speed run in at 50.3 on the gps, Might have a bit more in it but I stopped when the rpm's hit 7020 after almost 30 seconds of WOT.

I'll try again with the new one and let you know.

 

[jammin777]

thanks! my 97 gsx i had with stock prop did 56 -58 but that was on the dream o meter. but alot of it also depends on the altitude,
what is the elevation where you live? i guess it really doesn't matter but still looking forward to the result when you get your solas back.

 

[Mekanix]

I'm at sea level +- 500' .

Got it back and went out for a last ride.

Dream-o-meter says It topped out at 62 mph after a long run. Stock only did 58. Take it for what its worth

Made a huge difference in playing around power though.

I can actually spin out and accelerate in any direction instead of sitting there and frothing up the water

I can do the fun things with a near full tank of gas that I used to do with a nearly empty tank.

Rev limiter is harder to hit, and it likes to jump out of the hole.

With the stock prop on a speed run I managed to hit 7180 but backed off.
The solas got up to 7000 and stopped around there so I didn't hold it any longer.

With the solas it accelerates sooner and gets up to speed at a low-mid rpm and that's where it has most of the pull (45-5500). The engine sounds like its loaded instead of free reving. I could describe it as shifting up a gear.

The stock prop felt like it was weak down low but pulled in the mid-higher range.

Overall I'm really happy with the difference.

 

[Sportster-2001-951C-Stock]

I just cleaned my RAVE valves and found another 300RPM that I'd never seen before, for a new top speed of 50MPH on the dreamometer!

 

[jammin777]

thanks for the comparison Mekanix, that's exactly what i want in performance. i'm at 2600 ft elevation. it is 4400 ft where i camp but that would only be a few times a year so i can live with that. not sure if having fuel injection would help with that or not. the other ski i had was carbed.