Hey guys, I noticed today that it appears that the mixture gets too lean when I floor the accelerator to overtake somebody (and use the downshift switch). When the secondaries open up, the acceleration is not smooth, but a bit jerky. It appears it gets too lean or something. What could cause this? Spring tension of the secondaries (air valve) too tight? Too loose? The choke pull off diaphgragm is new and working fine. What else can I check?
Any smoke visible in the rear view mirror when this happens?
On my 1981 Corvette I pulled the secondary air valve rod off years ago and performance improved significantly!
Quote from: Julien Abrahams on September 03, 2014, 05:09:29 PM
Hey guys, I noticed today that it appears that the mixture gets too lean when I floor the accelerator to overtake somebody (and use the downshift switch). When the secondaries open up, the acceleration is not smooth, but a bit jerky.
Julien:
Your problem can just as easily be ignition as fuel. First step is to rule out one or the other and it is generally best to check the easiest stuff first. When you put a load on an engine and increase its speed and cylinder pressure the ignition system has to work harder to jump the gap. Dirty fouled plugs may start and run fine but "break up" under full throttle. Bad wires will do that, a coil on its way out can too.
Dan
Julien,
A SWAG would have me looking at the spring tension of the secondary air valve. If it is too loose, there can be quite a "bog" untill the engine speed catches up with the carburetor.
Greg Surfas
OK, but what is the bog actually? I'm thinking air spring tension as well, but how do I know whether it is correct? Just loosen/tighten it, and test run to see if it makes a difference?
Further: I cleaned and regapped the spark plugs a couple of weeks ago and the spark plug wires are about a year old. I put in new points last year as well (and adjusted the timing of the ignition and dwell angle a couple of weeks ago).