View Full Version : checking secondaries on 4bbl


magpi
May 17th, 01, 09:35 PM
I have an '83 Z28 w/ 305 and 4bbl, I'm experiencing prob's similar to previous post "backfiring out the carb". The car feels like it's only driving on 2bbls. My question - how do I check the accel pump? With engine off when should I see spray from both front and back, right now the front is squirting great but I don't see much spray in back even pumping the throttle all the way back & forth. Thanks for your help/comments.

RABarrett
May 18th, 01, 03:22 AM
Q jet carbs rear pump does not operate like the fronts. It operates from the depression created by the opening of the secondary air valves. As they open in relation to air demand, the space created by the valve and the air horn casring creates a depression which pulls fuel through an opening in the casting. If the engine is not running, it will not create any deprerssion, hence, no fuel flow. The easiest way to check secondary operation is to mechanically move the air valves and check the operation of the secondary metering rods, making sure they move with the air valves. Ray

CA420
May 18th, 01, 06:34 AM
He has a Holley.

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