I have a Q-jet that has been re-built. Also had new bushings put on the primary throttle shaft. Start the engine up warm and it idles fine at 700 rpm. Drive down the road and back and the engine wants to idle at 1000 to 1200 rpm. Push the secondary air valve open and the engine goes back to its 700 rpm idle speed. Let the air valve close and in 10 to 15 secs. the engine will start back to 1000 to 1200 rpm idle. Turn the engine off and re-start it and it will idle fine at 700 rpm,... until I drive it. Help please. Thanks
I put an old Q-Jet that I had on the engine, and it idles great. So I guess I better see what's wrong with the re-built Q-Jet. That wasn't suppose to happen. Trying to get one fixed-up and running good and more problems.
Who rebuilt the Q-Jet? Was it an over the counter job or from someone you know? Most over the counter jobs are junk.
Is it possible the engine is idling at the ragged edge of the machanical advance? I would try putting in a set of very heavy advance springs in the distributor and see if the problem goes away. Have you put a vacuum gauge on it?
The re-build was not an over the counter thing. Mostly my doing. I had Gessler put bushing on the primary throttle shaft but not the secondary. Partly because I did not see the secondary throttle shaft service listed on his web site. Partly because I didn't "feel" like the secondaries needed it. Gessler does offer the service and it looks like that is where I'm headed with this carb. Will try and let you know if this fixes the problem. Let's hope!
I do NOT recommend installing bushings on the secondary side of the q-jet. The factory left some clearance there for a reason. Just had a guy drive here yesterday from Northern Ohio with his freshly bushed baseplate, both sides. It was a "train wreck". There wasn't enough clearance at the secondary shaft to allow the huge throttle plates to "settle" into the bores each time they closed. He also did the "home brew" method, using a drill press and trying to line up the bores using an arbor, then following it with a drill bit. BAD deal all the way around, as a fluted bit just can't accurately follow a hole without a lead on it. Both shafts were off some, so we ended up replacing the throttle body......Cliff
