Hello, at my workplace we have a 1971 Riviera non-GS. It runs fine, gets decent mpg (at best 18 mpg during a 200 mile cruise@40-45 mph with a few coffee stops along the way), doesn't smell too rich from the exhaust etc. But it hesitates for about one second. At low speed driving when you lift the foot of the pedal and come back again you can ease on the throttle ever so gently and it almost wants to die. A faster depress from fully closed throttle - same thing. In highway speeds it is different, now it hesitates at kick down causing problems when overtaking. I wanted to adjust the accelerator pump, but quickly realized it is not the same as the Holley on my Buick 350. Sounds like a fuel surge? Or a timing issue?
Might be going lean from an accelerator pump issue - with the car off, get yourself over the carb inlet and look straight down into the primaries. Then open the throttle and you should see two strong streams of fuel, one in each primary bore. If you dont, then the pump skirt has to be replaced - not uncommon. Let us know please.
can you get a vacuum reading and rpm at idle? that tells a lot about carb and engine. accelerator pump was my 1st thought, but its squirting fine you say. when was the carb last rebuilt?
Speaking of vacuum, what should idle vacuums be for a mild 350 or 455? Sent from my iPhone using Tapatalk
