[YkDave]

Well, if you have seen my other post you know what the story is, if not here it is.

Picked up a tin boat the other day which someone had hacked a kawi jetski pump into, driven by a sled engine. upon research i discovered the donor jetski was an 87 js300.

Anyways, the thing was pretty sluggish in the water, partly due to a POS sled engine thats on there and partly because of a beat up pump.

Heres a few pics of it tore apart. It appears the impeller took the blunt of the damage, the housing has some minor scarring but nothing huge.

Im thinking of just cleaning up the impeller with a die grinder for now (cant get it much more out of balance than it is now) and throw it back together and try to get the motor running better or a different one on there to see if the pump is even going to do the job.

Are their any sort of RPM/HP limits to these pumps?

Right now with the way the drive setup is rigged it will give me a theoretical 15-16000rpm pump speed when the CVT clutches fully shift out!

 

[bpann1]

send the impeller to short block technologies and they will reman it for 25 bucks

Thats you problem that impeller is junk. there is no limit on rpms That whole set up is just wrong anyway. Is it cavitation or spinning out?


Remanufactured pwc engines, Rebuilt pwc engines - SBTontheWeb.com

 

[YkDave]

It appears that sbt only does the reman thing for stainless impellers and wont even accept an aluminum one as a core!

I have no problem dropping a couple hundred bucks on a good aftermarket impeller as long as i know this pump has the potential to do what i want it to. That is, move this 500lb+ (plus a couple guys and beer) at a decent speed...


Anyways, that impeller definately wasnt doing very good... I cleaned it up with the die grinder and its a whole different machine now. It can actually get the boat up on step with 2 guys in it!

On another note, the lil 294 doesnt have the power to get the CVT clutch to fully shift out and both the CVT belt and the pump drive belt would roast and slip after a little run. So i went and got a smaller drive pulley for the pump so now im running a 5.3" drive (compared to a 10.5") to a 5" driven pulley at the pump. Im hoping that will allow the CVT clutch to fully shift out and get things running a little better.

 

[bpann1]

Hmm

You should be good if the performance is better. No sense in spending the money on a new impeller unless you really want to. If you know what ski that came off of you can get a nujet replacement it is the cheapest.:appl:

 

[YkDave]

You say their are no limit on rpms, so i assume that means no limit on Hp since a guy can just keep driving the pump faster and faster the more hp he has...

What about, say 300HP?

I can pull the engine out of my sled (800cc turbo'd + more goodies) to drop on the boat but i dont want to get out in the middle of the lake and have the pump toss its cookies and sink the boat! A couple gallons of gas for that engine is worth more than what i payed for the boat, i would hate to loose the engine!

BTW, i was thinking a different impeller not only because this one is a little beat up, but i was thinking a guy might be better off getting something in the 18* range to move a little more water...?

 

[bpann1]

Starting from scratch.

Let's try this again. The reason I got so pissed is that I have spent 15 years learning and working on this stuff. I own a boat jetski and houseboat rental company so I pride myself in the knowledge. I had to go to the university of hard knocks to receive my doctorate in this stuff and I was just trying to help. I thought you were being a smart ass. Oh...I am not a yank. I live in Georgia getterdid.:appl:

We cool now?:thumbsup:

 

[YkDave]

Im not trying to be a smartass or anything, my knowledge in the field of axial flow pumps is somewhat limited because i dont usually play around with jetskis or jetboats a whole lot. im just trying to wrap my brain around a few basic things before i start spending a bunch of time tinkering with this pos, only to end up with a bigger pos!

 

[YkDave]

ok, again, no expert here but this is what i think is happening now...

With just me in the boat, 1:1 belt drive (pump speed around 8000) and its moving along pretty good. It seems like it starts cavitating every couple hundred feet even in pretty calm water, even worse if its choppy. It gets worse when i use the 2:1 belt drive...

It had been mentioned to me before to look into a scoop type grate because of how this thing was built, the grate is a good 1/2" (ish) up from the bottom of the hull.

I have come across this grate so far from worx...

Is their maybe another type out there that will be better?