Jeff jet 2.0

[Jeff B]

Revolutionary (in 1982) tapered wear ring/impeller

[spinner]

better performance with a taper - Hamiltons new HTX units going that way.

[Jeff B]

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[Jeff B]

There is always someone willing to exceed the manufacturer's recommendations HP/weight limit....

[Ross Goldsack - JBNZ Immediate Past President]

Karl doesn't look that heavy or powerful... the smokey old v6 doesn't either

[Ross Goldsack - JBNZ Immediate Past President]

etter performance with a taper - Hamiltons new HTX units going that way.
 

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[Jeff B]

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He means the impeller is smaller at the front Ross.....
Kawasaki di it on the 550 pump then again in the mid 90's on the ultra 150.
There was also a NZ built "Reactor" which was tapered, not that many built.
Not to be confused with the USA built "eliminator" which was multi stage and tapered but tapered the opposite way, from big to small...

[Jeff B]

Sticking some EVA on big boat and the offcuts fit the wee tub.
I was a bit worried about extra weight but at 150 grams its worth at least 1hp worth of bling factor.
Was careful not to cover up any welds.

[Jeff B]

Some more pics while I sit around.
Steering is a proper chain, wire rope, pulley setup. I used an inboard/outboard bellcrank and it works really well.
The std ski nozzle is a bit crappy (plastic) but steering is light and I'm happy with it.
Will pass tech A easy.

[Jeff B]

Just using a mesh screen filter for water feed to engine.
I have upsized all cooling lines and have the mesh pickup mod in stator.
Pre heating raw water in first 400mm of exhaust header but still had to reduce inlet orifice to 5mm to get a bit of temperature in the engine. I feel it's still running a bit cool but I'd rather that than a bit hot...

[Jeff B]

I still have the original old mikuni BN34 carb with 28mm venturi.
Most people say they are a pile of junk but after I dialed in the low and high speed screws it starts fine and runs fine, idles nicely and is responsive  so I'm thinking about leaving it?
I tried a 38mm motorcycle slide carb but the vibrations bounced the float and slide around too much and caused erratic mixture.
I might try the newer SBN38 carb but I dont feel I will get a lot more from it?

[Jeff B]

I haven't changed anything with the pump yet. Currently set up with very generous 30mm clearance, blade to stator vanes.
Have been told that the closer the better for performance and have seen/repaired a lot of smashed vanes with 3-5mm clearance here.
Has me wondering what performance affect it actually has??
I have some other different pitch impellers to try so might compare as it's easy to change diameter and clearance on this pump.
I really need some other boats to compare ...
At present waiting for mohawk, Karl and Henry to catch up with production so some competitive development can resume.

[powerband]

Hi, Jeff if you buy a fuel filter that has foam in it, break it open & cut it so it fits in the carb bowl around the main jet.  That will stop the aerating problem. I did it for the Finke Desert Race.   Paul.

[Henry]

Might put mine in the water race this arvo. All running and ready just no tubes.

[Jeff B]

Hi, Jeff if you buy a fuel filter that has foam in it, break it open & cut it so it fits in the carb bowl around the main jet.  That will stop the aerating problem. I did it for the Finke Desert Race.   Paul.

Hi Paul, good idea, does the foam act as a kind of surge protector/tank around the main jet? My problem is the engine vibration at idle is bouncing the float up/down which is causing the float level to rise and run rich/flood the bowl. Also the throttle slide is bouncing up and down which causes erratic throttle. Its quite a heavy brass slide and could probably be cured with a heavier spring but not keen on a heavier throttle pull.
Tried a Keihin bike carb with lighter aluminium slide which was better but not perfect and i feel it will wear quickly?

Ill see how Henry's 38mm SBN performs and if he exceeds 52.5km/hour i will have to up my game with performance mods.