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nzjetboating.com Forums => Tech Library => Topic started by: Matthewf/Norbert/TuiDog on September 30, 2012, 17:32:43 PM

Title: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on September 30, 2012, 17:32:43 PM
New section for small jet ski powered boat technical info

share you info, advice, drawings, photos of engines, hulls and jets here
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: vyrus-jet on September 30, 2012, 17:51:56 PM
kawasaki intake and pump
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: AlexC on October 01, 2012, 06:00:46 AM
Yamaha GP1200/XL1200  (97 and earlier) Stock has a 17/19 Impeller
Modified vs Stock with intermediate bearings
(https://lh3.googleusercontent.com/-fTnfpflW7Fw/Ttw9CRc1gSI/AAAAAAAAI1o/fdw0oLx2rqM/s640/P1000826.JPG)
(https://lh5.googleusercontent.com/-fGkThKdSCEA/Ttw9BteKwdI/AAAAAAAAI2I/kXfZGGF1heQ/s640/P1000825.JPG)
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: steely on October 06, 2012, 16:00:02 PM
could some of you experts out there post some pics and diamentions of your grills on ya jet ski boats please
oh and please state the size of pump  b> b>

cheers
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: roland on October 06, 2012, 16:20:03 PM
could some of you experts out there post some pics and diamentions of your grills on ya jet ski boats please
oh and please state the size of pump  b> b>

cheers

im no expert but mine has open area of 120mm x 300mm, 7 bars of 5mm thickness, seadoo rxp engine and pump,215hp supercharged.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Henry on October 06, 2012, 16:37:00 PM
200x350mm 25x6mm stainless bars 60hp 155mm diameter yamaha pump
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: roland on October 09, 2012, 10:14:29 AM
i have just replaced the old blade with a new solas,was going to change the wear ring at the same time but it looks ok, new blade has 0.15-0.2mm clearance,is that too much clearance???
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on October 09, 2012, 10:53:02 AM
sounds good roland, im running 2mm right now  >>@
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: roland on October 09, 2012, 11:09:39 AM
sounds good roland, im running 2mm right now  >>@

decided to put the new on in,might as well have all the variables known to get rid of this slipping, gap measures 0.05mm - 0.08mm, nice and tight :o
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: steely on October 10, 2012, 07:45:05 AM
sweet thanks for the info guys b>
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: vyrus-jet on October 10, 2012, 18:16:49 PM
10 ftr
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Brizz on October 11, 2012, 15:37:56 PM
im no expert but mine has open area of 120mm x 300mm, 7 bars of 5mm thickness, seadoo rxp engine and pump,215hp supercharged.
   At the risk of hijacking this thread that sounds like a very small grill area, eg the STX15 I pulled apart was 160hp and a 148mm pump and it had an intake area of approx 150mm 300mm with only 2 bars.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on October 11, 2012, 17:26:48 PM
kawasaki blades

shiny is solas 16/21

other one is stock
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on October 11, 2012, 17:34:07 PM
grill for kawasaki ultra (photo is of alloy r&d grill). works fine, bisalloy grill fitted to boat.

~285 L x 165 W  8 bars
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: careyl on October 21, 2012, 20:11:20 PM
Hi guys looking at getting into the small jet game and wondering which would be a better donor ski.
I heard Kawasaki skis are the go and have found a  kawasaki zxi1100 and a Kawasaki Ultra 150 for around the same money.
If someone could give advice on the pros and cons of each that would be great.
Cheers!
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on October 21, 2012, 20:20:53 PM
Hi guys looking at getting into the small jet game and wondering which would be a better donor ski.
I heard Kawasaki skis are the go and have found a  kawasaki zxi1100 and a Kawasaki Ultra 150 for around the same money.
If someone could give advice on the pros and cons of each that would be great.
Cheers!

Do you prefer "Ring ting ting"
or not

seriously though
what year and how many hours on each
what kinda condition etc
personally prefer 4 stroke
quiet boat = happy boat
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: careyl on October 21, 2012, 21:30:10 PM
Both look in not bad condition the ZXI1100 is a 96 and the Ultra 150 is a 2000 both look in not bad condition with 100 hours on each for $4500. What would you recommend? Looked into sr20 with colorado or similar but seems like these would be heavy in a 3m hull?
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: roland on October 21, 2012, 21:39:45 PM
get a seadoo rotax supercharged rxp
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on October 21, 2012, 22:13:35 PM
Both look in not bad condition the ZXI1100 is a 96 and the Ultra 150 is a 2000 both look in not bad condition with 100 hours on each for $4500. What would you recommend? Looked into sr20 with colorado or similar but seems like these would be heavy in a 3m hull?

inspect the jet pumps
look for damage to the wear rings,stators and impellers
I would go for the 15f depending on condition

Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on October 22, 2012, 21:05:17 PM
The ultra has an odd- ball pump with a tapered impeller, The 1100 ZXI and 900/1100 STX's all have the same 148mm pump.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: steely on October 25, 2012, 09:05:46 AM
well after nearly cooking my engine on the weekend due to a small stone blocking the 10mm cooling outlet on the unit i thought id better do what i should of done last week before i left c0H

i removed the standard fitting and welded up the 10mm hole, then scalloped a piece of 25mm pipe to fit above and marked where it would be fitted, then drilled 24 2.5mm holes within that area, then welded the pipe in place and tapped a thread in the open end for the fitting.
mabye a bit of overkill on the holes however it does allow 20 holes to be blocked and i still will have 10mm of area supplying water to the engine b>
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: PM on October 25, 2012, 10:57:50 AM
well after nearly cooking my engine on the weekend due to a small stone blocking the 10mm cooling outlet on the unit i thought id better do what i should of done last week before i left c0H

i removed the standard fitting and welded up the 10mm hole, then scalloped a piece of 25mm pipe to fit above and marked where it would be fitted, then drilled 24 2.5mm holes within that area, then welded the pipe in place and tapped a thread in the open end for the fitting.
mabye a bit of overkill on the holes however it does allow 20 holes to be blocked and i still will have 10mm of area supplying water to the engine b>

You may wish to check your math with regard to area. You'd only be able to 1/3 of the holes to give you the original area of the 10mm hole.

Your new setup gives 122.72mm2
Original setup gives 78.54mm2

ie; 4 x 2.5mm diameter holes does not give you the same area as 1 x 10mm diameter hole...
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: steely on October 25, 2012, 13:39:11 PM
true PM you are very right i dident even work it out, never did school c maths too dumb....
im a do it and see if it works sort of bloke

i should of worded my above post more along the lines of the standard system needed only one stone to block the line now it needs 24 sl
KISS
keep it simple stupid
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on October 25, 2012, 18:14:11 PM
Nice work Steely
that's pimpin b> O0
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: mohawk on October 25, 2012, 18:18:30 PM
Have you shown it too karl  cou ..
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on October 25, 2012, 19:35:36 PM
good work steely

poor cooling is what keeps jet ski shops rich!

i fitted a sand trap, works well.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on October 25, 2012, 20:00:18 PM
Have you shown it to karl??  cou ..

Is it the rocks in the water take off that's the problem???? l-l
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Cookie on October 25, 2012, 22:15:29 PM
I've fitted an irrigation filter to mine. I leave the drain tap part way open so it self cleans. Works well, and dirt cheap.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: mohawk on October 25, 2012, 22:24:49 PM
I've fitted an irrigation filter to mine. I leave the drain tap part way open so it self cleans. Works well, and dirt cheap.
Its getting water too the filter thats the problem with these units cookie.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Cookie on October 25, 2012, 23:06:49 PM
Ah yes - there is that too !!
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on October 26, 2012, 08:33:02 AM
Its getting water too the filter thats the problem with these units cookie.
Yep that is true. It is only a problem on rivers with fine gravel.

In theory the over temp alarm light should come on and the CDI rev limit to alert you to a problem. This setup worked well on the 750, but doesn't seem to work on the 1100's. Probably because there is no water flow for the temperature sensor to act on.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Brizz on November 01, 2012, 20:36:51 PM
Just looked at the STX pump and it has pretty much what steely has created except the hose outlet is bolt on.  I also intend to play around with some type of pressure switch between the pump and filter to warn of loss of water pressure. Will look for some type of switch off the shelf but may play around with a dishwasher water pressure sensor of which I have heaps.   *-)
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on November 02, 2012, 08:16:29 AM
Yep that is true. It is only a problem on rivers with fine gravel.

In theory the over temp alarm light should come on and the CDI rev limit to alert you to a problem. This setup worked well on the 750, but doesn't seem to work on the 1100's. Probably because there is no water flow for the temperature sensor to act on.
I have to correct this post as I found the fault with my setup when I ripped out all the redundant/extra wiring from the KATS system. One of the temp sensor wires going from the temp switch to the CDI and gauge unit was broken internally.  Replaced the wire so will be interesting to see how it goes.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Paul on November 02, 2012, 11:28:20 AM
I have to correct this post as I found the fault with my setup

Is the new (small holes) cooling takeoff sorted too?
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: AlexC on November 07, 2012, 16:31:37 PM
Another question that I often wonder is the intake grill size. I feel like it should be a ratio of the pump area, but the prop pitch might as well? Is there a rule of thumb for this? I've heard that if it's to big it can "burp" at high speeds, but to small and the velocities get to high and it aerates/cavitates.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on November 07, 2012, 16:36:28 PM
There is possibly a whole thesis that could be written (and probably has) to do with intake size,shape and the hydro dynamic efficiency of differing designs
the only proper way to approach this question is to test,test,test
 
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: AlexC on November 07, 2012, 18:21:44 PM
no generic rule for a ruff and dirty size on these small jetski boats eh? How are you sizing your intakes?
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on November 07, 2012, 18:26:18 PM
no generic rule for a ruff and dirty size on these small jetski boats eh? How are you sizing your intakes?

My way is to work out the cross sectional area of the original intake foot print
then add the cross sectional area of the edge of the grill bars and viola there you have it
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: souldoubt on November 11, 2012, 11:56:56 AM
Any thoughts on a Polaris 785 Pro for engine and pump.  140 hp 148 mm pump.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: mohawk on November 11, 2012, 12:34:33 PM
polaris pumps are good, possibly the best design as far as jetski units are concerned and the motors go like hell  b>
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on November 18, 2012, 20:13:03 PM
blades for kawasaki pump      left to right in photos      *kawasaki factory           *Solas           *Skat
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: heemi.v8 on November 22, 2012, 02:47:18 AM
 I like the shiny one b>
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on November 22, 2012, 08:24:48 AM
Kawasaki 1100 STX unit after 2 days gravel pumping on the Ngaruroro.

OD's are still OK but leading edge is a bit hooked.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on November 23, 2012, 00:37:35 AM
How does  stator look
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on November 23, 2012, 10:48:39 AM
It's fine.

I also have a Polaris unit (with a stainless stator) that I will modify to fit the Kawasaki intake, but stator wear doesn't seem to be an issue so I might hold off and use it for the next project.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Brizz on November 25, 2012, 19:51:30 PM
What changed performance wise with the blade like that...eg rev change....slippage or what  pop
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on November 25, 2012, 20:38:53 PM
What changed performance wise with the blade like that...eg rev change....slippage or what  pop
It is really hard to tell, because the grill is usually full of rocks, so any impeller slips.  That impeller pulled 6,950rpm (real rpm not the Kawasaki dreammeter!) new and still does the same. When the OD's wear badly can see 7,500rpm which is a bit high for the old 2 stroke.

Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on November 26, 2012, 19:42:10 PM
Kawasaki Ultra 250 jet unit water pickup
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on November 26, 2012, 21:11:36 PM
karl i run all 3 water pickups into a sand trap... works a treat and I then have redundancy if any get blocked
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on November 27, 2012, 21:36:49 PM
Just weighted a complete 1998 Kawasaki 1100 ZXI engine including  accelerator pedal/coupler but not the electrics box.  67.5 kg
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on November 27, 2012, 21:43:04 PM
Will you get Jeff to weld up those"CHOOKS" in the stator??
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on November 28, 2012, 08:14:10 AM
Its not my unit, tis just to show how the later model units do the water pickup.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jeremy williams on November 30, 2012, 14:33:08 PM
Hey guys , I dont know the legal issues or other road blocks that would be an issue , But I live in the U.S. on a lake, I can buy older model Jet skis and seadoo's cheap (less than $1000 for the 900cc +) and smaller 750 jet skis and 587 -787 seadoos for cheaper. I have the place to dismantle and ship parts, I dont know if this is even feasable but I would be willing to help if I can (sorta give back to the forum if I could) . Thanks,
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Clark on November 30, 2012, 14:42:46 PM
I might be interested in Kawa Ultra LX with the 15f motor... I'll send you an email.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on November 30, 2012, 18:17:30 PM
I might be interested in Kawa Ultra LX with the 15f motor... I'll send you an email.

oh o!    b>
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: mof on November 30, 2012, 18:39:24 PM
I might be interested in Kawa Ultra LX with the 15f motor... I'll send you an email.

Wot are you up to Clark... :-X :o
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: roland on November 30, 2012, 18:46:37 PM
for those that are looking at building a small boat and is looking for a donor boat, my previous boat has been written off by insurance and will be going up for auction at turners soon.
it has some really good gear in it, seadoo rxp 215 hp supercharged rotax engine and unit,plus all the running gear with trailer, heat exchanger,fuel tank etc.

IN MY OPINION i would not use the hull again as i think its not suited to braided rivers like we have here in Canterbury,i feel it amplifies any mistakes made,it has claimed 1 life and nearly another 2, this is a serious case of BUYER BEWARE,this boat is a killer,but has great gear in it which someone could pick up for a steal, i think they only want K5 for it.probably k10 of gear in it.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jappa on December 20, 2012, 17:54:49 PM
Will you get Jeff to weld up those"CHOOKS" in the stator??

Those are not "CHOOKS in the stator" they are supposed to be there and are from new......
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on December 20, 2012, 21:45:20 PM
Sorry mate I own one and they were definitely broken stator veins on mine
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on December 20, 2012, 22:09:39 PM
Sorry mate I own one and they were definitely broken stator veins on mine
mine have same issue... looks like a biggish stone got jammed and knocked all the pieces out?
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on December 20, 2012, 23:07:17 PM
I welded them up matt
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on December 21, 2012, 13:14:08 PM
Sorry mate I own one and they were definitely broken stator veins on mine
Jappa is correct, they were made like that from the factory (and yes he has one also!)

PIC of a brand new one attached

Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on December 21, 2012, 13:21:20 PM
You can read all about it here.

http://www.greenhulk.net/forums/showthread.php?t=19927&highlight=ultra%20250%20pump (http://www.greenhulk.net/forums/showthread.php?t=19927&highlight=ultra%20250%20pump)
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on December 21, 2012, 14:09:44 PM
cool dont need to fix mine then.. b>
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on December 21, 2012, 16:10:41 PM
Ok guys so when you look at the stator
and you find radiating cracks and fingernail sized irregular
pieces of stator chewed away
then this is all perfectly normal?????????
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Jeff B on December 21, 2012, 16:16:07 PM
Ok guys so when you look at the stator
and you find radiating cracks and fingernail sized irregular
pieces of stator chewed away
then this is all perfectly normal?????????
Yep, after 1 hour in Karls hands they all look like that ;). Would be hard to tell what the original profile was.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jetdesign on December 21, 2012, 16:50:13 PM
true that Jeff O))))
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Fuges on April 23, 2013, 19:46:58 PM
Just finishing a 3m jet boat with Kawasaki 900 running gear and have forgotten how it was plumbed up.
Can anyone tell me where the hose off the 3/8" outlet from the bottom of the exhaust expansion chamber is meant to go too? is it just out the back of the hull? if so what stops water from going back in when parked up,
Any help greatly appreciated.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: heemi.v8 on April 24, 2013, 13:21:57 PM
hi fuge,
i think there is a fitting somewhere on your engine that feeds water into this fitting. at least thats how my polaris is. see the hose in the bottom left of pic...
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Fuges on April 24, 2013, 17:02:01 PM
hi fuge,
i think there is a fitting somewhere on your engine that feeds water into this fitting. at least thats how my polaris is. see the hose in the bottom left of pic...

Thanks Heemi

From what I can see the fitting on the top that you are showing has a hose from the head to here, this is where you are meant to insert the garden hose to flush it ( this i dont understand as it would go straight out the exhaust ) .
The fitting I am lost with is out the bottom of the cast exhaust just before the hose to connect to the muffler box.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Jeff B on April 24, 2013, 20:25:04 PM
if the 900 is the same as the 1100kawi i'm pretty sure the hose you are talking of just exits out the back of the hull beside the jet unit. My 1100 did and i just copied the same setup when i put the running gear in a boat. There was another hose coming off the top of the exhaust which tee'd into 2 pipes, one fed water into the muffler and the other went through the over-temp sensor and then out the tell-tale on the side of the hull.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Fuges on April 25, 2013, 09:09:02 AM
Thanks Heemi

From what I can see the fitting on the top that you are showing has a hose from the head to here, this is where you are meant to insert the garden hose to flush it ( this i dont understand as it would go straight out the exhaust ) .
The fitting I am lost with is out the bottom of the cast exhaust just before the hose to connect to the muffler box.

cheers jeff thought that might be the case, any idea what stops water flowing back in when at a stand still?
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Jeff B on April 25, 2013, 18:30:56 PM
Nothing, i think it's just the water jacket outlet. It can't get up into the engine as the exhaust goes up higher.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: glocko on April 25, 2013, 18:57:06 PM
think that one is plumed into overheat sensor then back into exhaust or overboard.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jeremy williams on May 20, 2013, 15:40:15 PM
question on the intakes from jet skis.

is it better to fab one from scratch or remove one from a ski and modify it?

Just looking for opinions and pics of some built.

Thanks!
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: vyrus-jet on May 20, 2013, 17:14:33 PM
start from scratch, jetski ones are normally glass and part of the hull , or in the case of the yamaha cast alloy and very crappy/thin and prone to cracking
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Fuges on May 25, 2013, 13:49:44 PM
Hi All, got my 3m/900cc kawasaki boat in the water for the first time this morning, went pretty good top end but seems to cavitate quite a bit out of the hole and when cornering.
The intake i built is 400mmx150mm with 6mm bars and around 8mm gaps (is this to tight?)
Has near new impellor and wear ring.
I also have not put any planning strakes on yet, do these help at all with cavitation?
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on May 25, 2013, 13:53:53 PM
have you put urethane around the grill to stop air?

depending on design/luck of the grill, it may suck air in any case

Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Fuges on May 25, 2013, 13:59:17 PM
have you put urethane around the grill to stop air?

depending on design/luck of the grill, it may suck air in any case

Urethane around the grill?? is this to smooth the lead into the unit?
Have a sheet of polyethylene on the bottom and have shaped that into the unit.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on May 25, 2013, 14:29:25 PM
to stop air bleeding around grill edges
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Fuges on May 25, 2013, 20:05:07 PM
to stop air bleeding around grill edges

Cheers got it sorted, the unit is welded in so wasnt leaking there, was leaking through the rubber seal on the bearing housing, all sealed up now and will have another run tomorrow.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: jeremy williams on June 27, 2013, 07:26:46 AM
What type of steering set up are you guys using? A rack and pinion type? Thanks
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on September 20, 2013, 11:40:46 AM
http://www.google.com/patents/US8070538

Patent describing why the 155mm kawasaki pumps have the notched stator
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Paul on September 20, 2013, 20:59:32 PM
http://www.google.com/patents/US8070538

Patent describing why the 155mm kawasaki pumps have the notched stator

Nice find Karl.

So in summary, a limitation of the casting process, means they can't cast the high rake they would like (to reduce cavitation), at the outer of the leading edge of the stator vanes.  As they can't get the angle they want, the compromise is to remove leading edge metal, to get a greater distance between blade rear-edge and stator leading-edge, near the edge of the pump.

Are these castings die-cast or sand-cast?  My memory would say die-cast (they're fairly smooth), wheras the bigger units (e.g. Hamilton) are sand-cast.  Sand casting doesn't have this die-casting limitation, of needing to be able to remove the finished casting with the die still intact.  With sand casting the sand form is broken, allowing _any_ shape out, thus not a problem getting the stator vanes any shape needed with sand casting.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on September 20, 2013, 21:11:45 PM
im guessing the extra area at the the od gives room/lower pressure for expansion preventing boiling/cavitation
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Karl on September 20, 2013, 21:15:38 PM
After reading the article it wasn't clear to me why wouldn't you just space the impeller further forward? I.e bigger gap between the back of the impeller and the front of the stator.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Matthewf/Norbert/TuiDog on September 20, 2013, 21:29:00 PM
i think they are trying to reduce cav and increase efficiency at the OD high speeds whilst having tight clearance on the rest of the blade. maybe they are chasing the last fraction or mph....
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Paul on September 20, 2013, 21:44:10 PM
After reading the article it wasn't clear to me why wouldn't you just space the impeller further forward? I.e bigger gap between the back of the impeller and the front of the stator.

Quote
to reduce pressure loss by minimizing a distance between the impeller ... and the fairing vanes
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Dicko on June 04, 2014, 04:42:50 AM
The wear ring on my 15f has reached it's use by date, has anyone changed a wear ring on a 15f and was it difficult?
I can get a reconditioned stator with new bearings and a shaft for $400, but the bearings and shaft are fine, don't really want to fork out that kind of money, if I can change the wear ring, especially as it is going to be an ongoing problem.

I've checked out Youtube, it seems to have every other type of unit except the 15f.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: heemi.v8 on June 04, 2014, 12:35:42 PM
http://www.pwctoday.com/showthread.php?t=136633 (http://www.pwctoday.com/showthread.php?t=136633)

i find this hard to believe but these guys reckon you have to replace the whole thing...


on the seadoos you just put the stator in the freezer and the plastic liner pops out. then put the new liner in the freezer and it will push in by hand. if your on the river you can use a hammer and chisel carefully. this method requires the impeller to be removed.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: heemi.v8 on June 04, 2014, 12:38:42 PM
same thing here... http://ultra150.yuku.com/reply/25947/Re-Jet-Pump-Question#.U45mURaKxFw

if you do some research you may be able to get an aftermarket one that has plastic inserts. if not you can probably get your current one machined to fit sleeves off something else
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Jeff B on June 04, 2014, 14:26:53 PM
I have pulled out and replaced wear rings on Kawasaki 440cc and 750cc units, was pretty straight forward as when made, the unit was machined and then a wear ring pressed in.
Havn't done a 15f and i assumed they would be the same? Possibility that the wear ring is cast into the stator when manufactured?
If this is the case it will need to be machined out.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Dicko on June 04, 2014, 18:01:05 PM
 Thanks Jeff, I was thinking of buying a second hand stator and seeing if I could machine out the wear ring and replace it with a plastic type if possible, sand is my enemy here, so I will go through them fairly quickly .
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Jeff B on June 05, 2014, 14:28:45 PM
You can machine a new stainless wear ring out of a piece of 6'' SCH80 pipe, not exactly cheap though.
I would say machine it out to take standard seadoo wear rings, are they 155mm or 155.5mm? You can get plactic or stainless ones fairly cheaply off the shelf.
I just bought a brand new 159mm seadoo unit with wear ring for $530 landed in NZ. Main reason was the readily available impellers/wear rings.
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: Dicko on June 05, 2014, 16:51:08 PM
Thanks for your help Jeff
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: MRM on April 28, 2018, 08:42:02 AM
Pump diameter and impeller info for all skis

http://www.atlanticjetsport.com/index.php?l=product_list&c=405
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: MRM on April 28, 2018, 11:17:53 AM
New Polaris pump parts now made by Weber (new 148mm stainless stators)

https://sites.google.com/site/polarispwcknowedge/Home/first-things-to-do/keeping-your-polaris-pwc-on-the-water/jet-pump/alternate-polaris-oem-jet-pump-parts-source-weber
Title: Re: WEE Boats - Engines Jet Unit Tech info
Post by: MRM on November 28, 2018, 21:20:29 PM
Random fact... an stx12f engine weighs 86kg ready to run.
I guess the 15f would be bloody close to that too.