Power valve function and what ops. it?
 

Does it enrich the mixture during early throttle?

The power valve enriches the main metering system when it senses low manifold vacuum (heavy on the gas pulling into traffic, going up a hill).

Thank you for your expertise. I know my PV is good because it's new and it holds a vacuum but compared to the old one I removed when I installed the rebuild kit in my carb this new one looks much more restrictive at the floor of the bowl, i.e. the old one, which also held a vacuum, looked like it had very little restriction in the floor of the4 bowl, just the top of a spring retainer. The new one has a brass looking top on it which almost occludes the floor of the bowl hole. My power going up a hill and starting out is lousy. The accelerator pump is new and seem to work well.

There are different calibrations for power valves. You can buy separate power valves that open at different vacuum levels. The generic one in your rebuild kit may not be the same sensitivity as the one that was originally in your carb.

Your off-idle performance is going to have more to do with the accelerator pump than the power valve. The power valve won't kick in until the throttle plates are way open and manifold vacuum drops.

Hi,
Do you still have the original PV? There should be a number on it like "65" or simular. This is the vacuum level needed to operate it. 65 = 6.5 inchs of vacuum. Compare the numbers of old to new valves.

Lee

Thanks Lee. I'll check it out.