There are several possibilities. The chokes are not fully operating,
check for full travel. The carb passages are partially plugged. The
float levels are wrong. Air leaks in the intake or carbs. There is a
pretty good tech on the HD8 carbs here:
> I wonder if anyone can help me on my starting problem on my '65 BJ8?
> It takes alot of cranking to start and full choke, even in the summer. In the
> fall and winter it's worse. It has been doing this for several years now. I
> have had the car since around 1990 and it always started fine. I think this
> has been a gradual change over the years.
> I did a major tune-up recently: points, plugs, cap, rotor, condensor, ignition
> leads, and it helped only slightly.
> When it starts, it takes full choke and it needs more. After 5 or 6 tries it
> will fire a little longer each time, and then it will start running, but it
> sounds like it is only on 1 carb. After 15-30 seconds, the other carb kicks
> in and it runs fine. Once it is running, it runs great at all speeds.
> Anybody have any suggestions?
> Frank Magnusson
> Wichita, KS.
> '65 BJ8