Trouble with Carter AVS Secondaries

[Archie340]

Seems no matter how much I try adjusting the secondary air door on my 6125 AVS the motor surge's/bucks. You can feel the power is there but it immediately starts hesitating and feels like I'm just beating on the motor. I rebuilt the carb last year and it runs perfect on just the primaries. Replaced the fuel filter, did a recent tuneup and checked carb linkage for binding. At idle I can crack open the secondaries and everything seems fine. All I can think is it's a fuel pressure issue, engine is a 71 383HP. Thoughts?

 

[rumblefish360]

Did you readjust the butterflies to open up more?
Double check for obstructions in the fuel passage ways.
Make sure the jets are in and the baffles in place.
Float drop is correct and needle and seat are clear.

 

[RJRENTON]

Archie,
The original Carter AVS was a wonderful carb. The replacement Edlebrock AVS is ok but the construction & operation is slightly different. The previous person mentioned float drop have you checked it? If the engine is surging / stumbling during transition to secondary operation, and if the secondary AIR VALVE is adjusted correctly, the issue MAY be the float levels are too low, which causes the fuel flow to begin later, resulting a lean condition. Are the secondary jets correct? Have you "read" the spark plugs. If the insulator is white to very light tan colored, is usually an indication of a lean fuel mix. Spark advance and temperature also contribute to the spark plug coloration. What condition is the manifold carb gasket. Is there a vacuum leak. PM if you want to discuss...
Cheers,
RJ Renton

 

[Meep-Meep]

Certainly check fuel pressure at idle and while under load. Are the secondary jets the correct size?

 

[lewtot184]

Certainly check fuel pressure at idle and while under load. Are the secondary jets the correct size?

this!

 

[Archie340]

Thanks for the great information. I also replaced the fuel pump, no change. Took the car in the shop for a different reason and just mentioned the problem with the carb. I got the car back and now the secondaries are working fine. I'll have to ask what they did as I didn't even know it was corrected till I drove it away. Probably the air door I couldn't seem to get right.

 

[moper]

If it's stumbling and the floats are set right - the door's opening too fast and needs more tension. If you floor it in nuetral and run it up to 3-4K you shoulld not see the air door begin to open. If it opens, it's too loose.