is the main jet on these carbs adjustable? in the rebuild it says just to screw it back in while on the idle adj snug an back out 1 1/2 turns.

 

Bendix made an adjustable main and a fixed main carb. Mine happens to be the fixed main. If you have the adjustable main you'll by having two adjustable mixture screws on top of the carb. The one closest to the engine is the idle mix and the other one is the main. Some look like they have the adjustable main because the idle tube on some is removable from the top. So if you have two screws on top of the carb and they both have springs under them, you have the carb with adjustable main.

 

If yours has a fixed main jet, you're limited to making adjustments by changing to larger or smaller sizes. For example I'm jetted for 1,100 feet above sea level. Any time I travel in the mountains and exceed 5-6,000 feet I have to change to a smaller size (less fuel to match less air) then change back when descending. If you put on a high flow air cleaner and exhaust (more air flow) you may need the next size up (more fuel).

There are adjustable main jet kits available but I've not tried one.

 

That's right, I had forgotten about that. I thought about it at one time but then decided I would buy an adjustable main carb to see if I really thought it was necessary rather than experiment on my known good carb with the adjustable kit.