Expert: Van - 9/17/2005

Question
  My 69 chevy p/u has a 250 6cyl. It always ran great until recently. It will start, idle rough, smooth out in seconds, run great, warm up and barely run at all. That will be it. Once hot, I might get it to smooth out once in 20 times. It has a new carb, gas lines,fuel filter, fuel pump, cap, rotor, points, wires, plugs. I just dont know. It feels like it is either running out of gas or loosing spark. It will even backfire. I cannot find a vacuume leak, the pump seems to push fuel fine.

Answer
Hi Bob,
I realize you have a new carb, but if there is something causing the float in the carb to stick or not work correctly, that could be the problem.
Some floats could soak up fuel, and become heavy, causing a high float level. Some brass floats can have a leak and get full of fuel, causing the same thing.

But the float level may sure need to be checked, as well as the condition of the float.
It could also be set too low, causing not enough fuel in the bowl.
There is a little scale even for weighing the composite or cork floats.

And the adjustments for automatic choke, vacuum choke pulloff, and idle air are pretty touchy, and must be done correctly.
And the float adjustment can measure perfect, but if the float is heavy, it won't float correctly, so checking it real soon after removing it is important, before fuel can leak or evaporate out of it.

Van