no bottom end power!

[Kyle c]

so i just picked up my first freestyle ski, its a brawler with A 760 motor with a b pipe and tdr waterbox, it ias a 146 pump, i seem to have no low end hit, i can barley get it out of the water where on my 701 superjet i can jump a couple feet on flat water, the motor sounds like its reving out then the pump catches up to it, anyone have any ideas on where to start?

 

[iQRTurbo]

Is your pump sealed up to the pump shoe? If it’s sucking air and impeller is cavitating it won’t hook up, especially on the bottom end

 

[newbee]

What prop is the pump in good shape?

 

[Kyle c]

I’ll have to get a better look at the shoe, and not 100% what kind of prop, but it looks to be in fantastic condition

 

[Kyle c]

My top end seems to be pretty good it’s quick, but it takes a bit to get there, not the arm jerker I was expecting

 

[Kyle c]

Pulled the ride plate and intake grate the pump shoe seems to be sealed up pretty good, the wear ring seems to be in good shape too, kinda outta ideas at this point

 

[Kyle c]

I just got the ski and the guy before didn’t have much info on it, it’s running 185 per cyl, is there anyway to check the pitch without pulling the prop?
I have yet to pull the head to see if ported

 

[newbee]

Ask the guy you got the ski from? Maybe he remembers

 

[Kyle c]

I did, he got the ski in a trade deal, he didn’t build it

 

[Kyle c]

Thanks for the info! I’ll have to check it, How big of a difference would running dual carbs be like my 62t?

 

[newbee]

I always thought single carb was better for bottom end. Dual just helps out breath more running wide open

 

[Kyle c]

Good to know, is a 760 underpowered for a 146 pump?

 

[Kyle c]

I’ll have to dig into this ski alittle more, thanks for all the reply’s! Much appreciated

 

[Big Kahuna]

Wait, 146mm pump? Never heard of such. But I am gonna say if it is 146, you do not have enough motor to push it, it could be prop pitch.........

You have a Frankenstein motor. 61x bottom end with a 760 top end. 760 is a great motor in a couch. But if not setup correctly in a standup, it is just not going to have good bottom end hit. With the right setup, a big bored 61x cylinder punched to 754cc's with 61x cases can and does work really well. But I do not believe you have this package. What motor setup do you have in your SJ?

 

[Kyle c]

I believe it’s a 62t bottom with 61x top, still a 701, lightened flywheel, b pipe tdr waterbox, air intake, Aftermarket prop(unsure of pitch) and a quick steer system r

 

[Big Kahuna]

Kyle, That picture of the motor is a 61X bottom end....... 61x intakes is a flat plate with the carb mount on the top........... 62T intake track is on the side of the cases.......

 

[Kyle c]

Yes In the brawler, but you asked for my superjet setup lol

 

[Big Kahuna]

Sorry, I thought you were coming back and saying "It is not a 61x, but a 62T"

Might want to consider doing a complete motor and driveline swap.

 

[be_lain]

That intake manifold looks like it’s from a 650 (6m6). The 61x intake manifold has a sort of raised beveled profile that sits above the bolt mounting surfaces. 650 intakes are flat all the way across (same profile as bolt mounting surfaces). If it is a 650 intake, the reed cages are much smaller than 61X and can be restricting your low end power. Maybe look into that a little further

 

[headshock]

From your initial post: Check your Pump shoe for Cracks, Remove Pump check pump seal. Look for anything that might cause cavitation. What do the back of the impeller blades look like?