Since a few week-ends, i'm fighting with the carb of the Capri.
Original carb was full of deposits and i wasn't able to clean it well, so i bought another, rebuilt, Holley 5200.
The "new" carb is supposed to be a '76 Mustang one, except it doesn't have all the emission stuff of the '80 one and it's jeted way leaner (140p/132s instead of 179p/223s), it's the same carb, maybe with a bigger primary according to some internet sources (for me, looks exactly the same size).
Problem i encounter is dealing with idle speed and mixture screw.
My idle mixture screw doesn't seem to be of any effect when i try to lean it. I can close it fully and still have the engine idle, no effect on idle speed no matter which way i turn it. When i screw it counter-clockwise, vacuum goes up a bit and around 1t, starts to lower. Screw it clockwise 1/4t before it lowers but still idleing pig rich.
Can lower the idle down to 1200rpm Neutral (21inHg), below, engine stumble (vacuum goes down to 15inHg, fluctuating up to 4-5inHg).
Disassembled the carb today again. Transfer slot is not exposed on primary, secondary is slightly opened according to a rebuilt kit notice i have (adjusting screw seated + 1/4 turn). Checked float (brass) level, made it a bit low so not to flood the bowl.
Car can run in this configuration, but mpg is close from the V8 ... not exactly what i need for a daily driver ...
Choke is deactivated and all tune is done engine "hot".
Vacuum advance is on manifold vacuum ... had heating problem previously when trying to run on ported vacuum ...
Someone has an idea of what could be wrong ?