The Stovebolt Site Forums The Shop Area Engine Shop what's it called and what does it do?

on the zenith carb, on the bottom rim, there's a small brass slotted screw with a hole in it. at least there's supposed to be. mine's missing. what does it do? i notice the carb sometimes idles too fast, but will slow down if i blip the throttle. could this be the cause?

well, since i got no takers yet, i'll add more info to possibly help out.
with the engine off, the throttle comes back to the correct idle position every time. but, with the engine running, it won't return without the blip, but you can force it back down easily. like the vacuum going through the throat is somehow strong enough to hold the plate open despite the big spring on the linkage connected to the bottom of the oil pan! maybe i gotta get a bigger spring?

I've got a 37 with a 261 and I believe we both have a mechanical bell crank set up for the throttle. I have had trouble for years getting mine to work correctly. The problem is partially due to running two carbs with a partially homemade linkage set up. The only solution I ever found was a bigger spring, too! Still I, too, had to "blip" the gas pedal to slow the idle. I finally rebuilt the throttle linkage using ball joint ends at the bellcrank and the carbs along with a bolt through an eyebolt at the end of the of the throttle shaft where it attaches to the bell crank. Now I have a smooth operating throttle with a normal off the shelf throttle spring, but I had to reinvent the stock one to get it to work right. A rework may be in your future.

Joe

The "blip" you have to do is a result of the butterfly shaft being worn. Only way to fix it is to take the shaft out, drill and install a bushing in the bore where the shaft rides.

okay, sounds great. i attempted to remove the 2 screws in the butterfly and them both stripped right off. i drilled them to get the shaft out. now what do i do?