The idle AFR is set too lean. or the exhayst system is leaking, throwiing off the O2 sensor reading at idle.
reset the idle mix srews for best idle quality and best idle manifold vacuum.
The resulting AFR should end up being 12.5 to 13.8:1 @ idle. 15:1 is too lean at idle (or the exhaust is leaking)
The priority at idle is idle quality and manfold vacuum at idle not a perfect afr at idle.
any small ex leak will throw offf the idle AFR. false lean.
AFR at part throttle cruise When you are cruising slow, you are still on the idle circuit.
If you want to try leaning down the primary part throttle crusie AFR use a primary rod with a larger cruise diameter but the same power tip diamter.
This leans the cruise.
To get an idea of when the primary jets start working, look down the carb while opening the throttle from idle
note the rpm and throttle angle where you start to see fuel flow from the primary main nozzles..
do no use over drive at low speeds. keep the rpms up. its got a big cam and wants to rev.
Last edited by F-BIRD'88; 05-02-2013 at 02:52 AM.