383 flat spot

[S&S62biscayne]

My 383 now and then will develope a flat spot just as you go to take off.
it always does it down low from idle as you accelerate slowly you can feel it and if i dont feather it it will stall.
Most of the time its fine.

It has a brand new 650 mighty demon fitted .
Any ideas

[cffisher]

Does this happen after it warms up?

[erik erikson]

My 383 now and then will develope a flat spot just as you go to take off.
it always does it down low from idle as you accelerate slowly you can feel it and if i dont feather it it will stall.
Most of the time its fine.

It has a brand new 650 mighty demon fitted .
Any ideas

First have you checked your fuel level in the bowls?
If this is correct then look at your accelerator pump.
Or it could be a squirter size problem.

[R Pope]

Good point about warming up. Does it do it when you first drive away? Carbs will do that, people who are used to FI don't expect it.