FE - Weber Help

[snapperlr]

Webers are new for me so definitely need a little help. I have a problem that we are having touble diagnosing. It may be carbs and it may not. Here goes, the engine is a 410 with Edelbrock heads. Ignition is MSD 6a with MSD mechanical advance dizzy. Carbs are 4 48 IDA's. Current set up is:

165 mains
65 idles
120 holders
210 collectors
55 bypasses
f7 tubes
37mm chokes
third prog hole drilled


My present problem is more significant than tuning. The car is running on only 5 clylinders at idle when the timing is set at a normal advance(15-20btdc). Idle mixture screws have no impact at all on three cylinders. However, if you reated the timing to around tdc the remaining cylinders will pick up, but as you would expect the car runs too poorly to even work with. One question I have is, are there passages in the IDA's on the idle circuit that are hard to clean? Could that be the problem? Any help would be terrific.

Thanks.

[Rick Parker]

We will assume (?) the the overall condition of the engine is good and compression is close to equal on all cylinders. That being the case have you checked the air draw to be equal through the carbs with a carb syncronizer? If so remeove the idle mixture screws on the cylinders in question and the idle jet and air corrector. Drain the fuel from the carb and blow air into the threaded hole for the mixture screw and also through the area where the idle jet fits.
Sometimes the jets do not properly seal in the bottom of the carb creating an internal vacume leak. With a flashlight, look into the jet bore at the bottom for a "shinny" circle indicating it is seating properly. You can also mark the tapered end of the jet itself fully with a felt tip pen, pull the jet out slightly from the holder and screw it into the carb until it is fullly seated, then remove and look at the end of the jet to see if it is marked around the circumfrence.