King Demon carb help please. Jet sizes?

[Boatmanrand]

Running a 28 ft. catamaran with 622 Chevy Tall deck 14-71 Moonyham Blower with twin King Demon 1095CFM carbs. She runs great but blows black fuel soot all over back of boat. It has .90 main jets in it. looking to lean it down without burning a piston. Any help would be great.

[curtisreed]

If it were me I would step down 2 sizes at a time until I started getting close. Then you can start working to the point of being able to read the plugs for jetting. Just don't load the engine super hard after a jet change. I have never tuned in a boat, but this is how I would approach it.

Curtis

[Boatmanrand]

Thanks for your help I will do just that.

[annamarks]

you can start working to the point of being able to read the plugs for jetting. Just don't load the engine super hard after a jet change.


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