Aqua question : Who knows shit about Propellors??

[Bombsquad]

Anyone know much about the pitch of propellers?? Im building a new jetunit for one of my skis and have been told by the experts its not gonna work but I have nothing to loose by trying, so...

The engine is a 701cc twin cyl 2 stroke, (twin carbs, b-pipe etc) round 80 horsepower. Usually runs a 144mm jetunit, but im building a 155 (usually found in 1100cc skis).

Apparently the NZ experts think my motor wont have enough grunt to spin up a 155 and that im wasting my time, though the americans seem to run them with 760cc motors and have no worries, and a 70hp motor on a 15 foot boat gets it along fine, so I dont see why with the right pitch of prop it wont work.

How do I know what sort of pitch to look for?? anyone had any experiance with either boats or jetunits

[kiwi808]

So I gues we are talking Piano here (Yamaha) and are you setting this up for freestyle? Depending on what you want will depend on your pitch etc.

In England I used to have a 750 sxi pro bored out to 800 running 46's factory dry pipe etc. My prop was a custom solas to increase top speed.

All the Piano Huggers (freestylers) used to have a different prop pitch from us racers as they all want acceleration and no top speed.

Shameless photo drop.

[Bombsquad]

Nice Ski, and yes it is a Yamaha however this one is a race spec Waveraider ive built up for my girlfriend (I have a worked up Fx1 as my freestyle ski).

It doesnt need a great deal of low end and I figure it will be a fine line between moving and loading up the motor/mid shaft too much (though it would be nice if it could still tow a biscuit).

It had fuck all top end with the old jet unit in it though, the fx1 would leave it for dust in a race

[kiwi808]

Did it have a Stainless Prop or the stock one and did it have any nicks/dents? A damaged prop even just slightly can take 5mph off you top speed and the stock props are crap. They are all down tuned. Upgrading to a skat-trak or Sola prop wll make a big difference.

Also when you talking low horse numbers, you will struggle to spin that 155mm prop. Don't they come on the big sofas that are 4 stroke and supercharged etc? Also the design of the hull will limit your top speed doesn't matter how much hosres you have. For example my ski probably had a top speed of about 55-60mph even though I was well over 100hp. They shape of the hull was the restriction.

What year piano is it? if it is an older shape then your hull might need hull extension front sponsons etc.

Also this is what my mate Ant Burges did on a piano.

[Bombsquad]

Raiders are a mid sized 2 seater sitdown, not really much bigger than a Blaster2. They had two engine options, either 701cc or 1100cc (three cyl two stroke), with the 155 pump being factory on the 1100 model. I have two 155 pumps, one has a stock prop and one has a stainless Solas.

Basically the 155 pumps owe me nothing, so Im going to fire them together and see what happens, but if i could find a good prop pitch before putting together nd back in the hull that would make life good

[kiwi808]

What are the pump/gaps like? If the gap between the pump and the solas is good (ie doent rub but can't get a peice of paper between pump and prop) then I would just go with what you have got. That Solas prop will hopefully be set-up for the sit down so I wouldn't really bother too much with the pitch. "it is what it is".

I had Charlie Nott-Bower set up my engine once it was rebuilt and he custom made the prop for me, had it balanced etc. The prop cost nearly £300 to set-up ($600+nzd) and the prop is ALWAYS the last thing you do becasue you have to have the ski all set-up tuned etc so that you care getting the best prop for the job.

However a lot of the guys i used to race with just used out of the box props to great effect. So If I was you I would get the ski together, see if it works before stuffing around with the prop. It's pretty quick to pull the pump out. And it would suck if you found out that there was no improvement with the bigger pump unit, or worse your getting mean calvating probles etc.

Also some lol pics of me on Ants Piano.

[Bombsquad]

To be honest i would be totally happy if there was no improvement and it ran the same as it did lol, Im actually not doing it to gain anything.

Im doing it as i dont have and cant find a factory 701 pump unit. The ski was a factory 1100 but I brought it with no motor and put a 701 in it cos i had one there (1100s cost moonbeams), I ran a 701 pump in it for awhile but that got sold with another ski I had so im now essentially making the best of what ive got and trying to avoid it becoming useless

[kiwi808]

O.k. now I understand. Isn't the 701 pump unit the same on all Pianos? ie: couldn't you get one out of a Super Jet?

Otherwise I would put it back together and see what happens. Your motor will either spin the prop or it won't but it has to be better then not running at all. I would also consider trying both the stoc prop and the Solas one, as there will be a difference and seeing as you are using a smaller engine with a bigger pump, you might want to de-tune so you don't cook you motor. Otherwise I could spend all night talking Jet Ski, or PWC's in your case (as only Kawasaki make Jet Ski's). *friendly joking*

I'd be really interested to hear if it works or not. I miss my jet skis and wish I had brought them back to NZ.

[dohcturbo626]

Give mi old man a buzz at Abel engineering Feilding he has been riding skis since way bck in the 550 Kawasaki days and don't know any1 tht can ryd a pole ski better we reline pumps nd weld up damaged props all the time we can even custom pitch stainless props we have almost every hull Yamaha made for the 701 including a perfect graphic fx1 nd mi personal fav blaster 1.