The Stovebolt Site Forums The Shop Area Engine Shop Zenith carb won't idle properly-1950 270 engine

Here's what I have discovered so far:

1. Due to my careless assembly of the carb during rebuild, the idling jet wasn't tightened down all the way to contact the jet calibration seat. That couldn't have helped the idling any. No sign of blockage in the fuel passages.

2. The idling mixture screw supplied with the rebuild kit didn't have the exact same profile as the old one that I took out. The new one wouldn't screw in as far. I put the old one back in.

3. The pump piston supplied with the rebuild kit with some sort of plastic diaphragm on it stuck in the well and wouldn't depress. Hence, no functioning accelerating system. Maybe the ethanol in modern gas caused it to stick, maybe it's just old. The kit came with directions to rebuild a 1974 Opel. I still have the old metal pump piston that I have epoxied onto a new pump rod. Same overall length as the original.

I don't know yet that these modifications will fix all of the issues with this carb, but I doubt that it will run worse. I haven't had a chance to test drive yet but I will report back. For the record, this was a Walker rebuild kit from Carburetor Factory. I'm not sure that I'd buy another one from them.