Help with carb setup please

[Adidasandy]

Hey, after a long few years out the game due to a broken back I've finally bought another blaster project.
Engine will be running a 701 61X with 1mm oversize pistons (82mm) and a single 46mm carb with AM head and Riva red pipe and will be solely for surf.
Question is what would be a good base to setup carb?
The carb I have has not been setup to this motor as it's an old carb I have had lying around.
Main = 142.5
Pilot = 120
Needle = 2.5
pop off = 11psi (65g spring)
high screw = 1.5
Low screw = 1

 

[Jr.]

Im assuming its an X case, unported 61x cyl?

Try this
Main 150 H adj 1 T out
Pilot 112.5 L adj 1.5 T out
2.0 N/s 95 grm spring
Should be pretty close?

 

[Adidasandy]

Thanks Jr. It's a 701 61X motor but didn't mention it's running 1mm over size (82mm)

 

[Jr.]

The additional bore Dia will be minor. Slight screw adjustment at most.

 

[Adidasandy]

Im assuming its an X case, unported 61x cyl?

Try this
Main 150 H adj 1 T out
Pilot 112.5 L adj 1.5 T out
2.0 N/s 95 grm spring
Should be pretty close?

How do you get the numbers to what it should be. Not doubting just would love to know the logic.

 

[Jr.]

How do you get the numbers to what it should be. Not doubting just would love to know the logic.

I have been building and tuning skiis for close to 30 years. This is out of my database of first hand experience.
There are formulas as to how many parts air vs parts fuel ect. Those formulas in my experiance are just baselines.
A watercraft is unique to other vehicles as the motor is in an enclosed, extremely humid, hot, oxygen starved enviorment. It doesnt really like to run like that, So, initially, a lot of trial and error happens once you calculate that formula baseline. The spec I stated to you, side steps that trial and error, as I have built skiis and ran that spec Successfully, On watercraft with a build list as you have stated.

Ski ya, Paul

 

[Adidasandy]

Right, engine in and carried out water test. Plugs are black and oily slime but ski runs well apart from a very slight flat spot when I pin it.
I think I need to adjust the H screw but which way? I'm thinking clockwise to limit fuel?

 

[mikidymac]

Yes, clockwise or turning it in will give it less fuel.