quote:Originally posted by Johnny Woods:
My Cleveland has never been responsive from idle. There has always been a very slight hesitation before it revs.
When I built the engine 15000 miles ago, I bought a new 600 vacuum secondary from summit. I took advice at the time and added a secondary metering block. My jets are 68 primaries, and 72 secondarys. Other than that I have not changed anything on the carb.
Any ideas what I need to change?
Thanks, Johnny
Johnny,
There is an accelerator pump cam problem on many Holley 600 CFM carbs. I wrote them an email about it but they never responded so I don’t know if they fixed it on the newer production carbs.
Take a close look at accelerator pump arm that should be in contact with the adjustable accelerator pump cam. You may find that the arm is resting on the coil spring that is around the throttle shaft and is being held off the cam surface. As you slowly open the throttle it moves pretty far before the cam can contact the pump arm and move the accelerator and causes a stumble as you go off idle. The only solution I could find was to install a cam from an old Holley that was larger and extended above the spring.
Mike