https://www.youtube.com/watch?v=ELXqNWEpAR4
My 1950 8BA flathead is chugging after it warms up. I have the original 8BA labeled carburetor and glass fuel bowl. After I sit on the side of the road for about 5 min and let it just idle it will let me get enough RPM and feather the clutch to "GET HOME" about 1 mile at a time. It seems like there is a sweetspot in the throttle that I can feather the pedal to get down the road and it will happen again. Once it cools down it starts like a dream and will idle all week.
My first thought is the fuel pump.
This is my first flat head and would appreciate a lesson or two.
The stumble is there when I first start but not as bad. It will idle all day but when it warms up it really chugs and becomes impossible to drive.
I Have tried disconnecting the vacuum advance and driving but there was no change.
Maybe fuel pump??