Engines surging before secondaries open

[KJnSTL]

Both of my engines surge from 3200 to 3800 RPMs. When I advance the throttle and the 4 barrels open up they accelerate great.

Background:
1989 Wellcraft St. Tropez
Two new long blocks
Original intakes
New quadrajet carbs
new exhaust
new ignition components on old distributor bases
Original ingnition modules
new fuel pump on P engine
P reverse and S standard rotation
timing set on each at 10 BTDC

I originally thought that I had a fuel delivery issue but the engines perform great once the secondaries open up.

Ideas on what to try...???

 

[Bondo]

Re: Engines surging before secondaries open

Both of my engines surge from 3200 to 3800 RPMs. When I advance the throttle and the 4 barrels open up they accelerate great.

Background:
1989 Wellcraft St. Tropez
Two new long blocks
Original intakes
New quadrajet carbs
new exhaust
new ignition components on old distributor bases
Original ingnition modules
new fuel pump on P engine
P reverse and S standard rotation
timing set on each at 10 BTDC

I originally thought that I had a fuel delivery issue but the engines perform great once the secondaries open up.

Ideas on what to try...???

Ayuh,.... Welcome Aboard,.... I think yer on the Right track,...

Carbs have several circuits, Idle, mid-range, 'n the 2ndaries,... 'n of course, the choke,...

I'm guessin' yer carb is set up too lean in it's mid-range,...