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Discussion Starter #1
I'm trying to set the idle mixture on my #1405. I turned the left screw in till it bottomed out, but the engine didn't stall or stumble. I then turned the right screw till it bottomed and the engine did stall. I had to back it out 3 turns to get it to idle decent. Does anybody know how far I should back out the mixture screws? I'm used to adjusting Holley's with the 1-1/2 turn rule. The engine's idle vacuum in neutral is only 10 h.g and idle in park is 8 h.g. The price I have to pay with a somewhat hot cam. I will try weaker step-up springs as recommended by Edelbrock with engines lower than 11 h.g. of vacuum.

'68 Coupe, 289, C4, 3.40 gears, GT-40P heads, TCI Streetfighter stall convertor.
 

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My experience with Carter/Edelbrocks is that you should turn the screw in until the idle speeds up. Continue turning slowly until it starts to falter. Back it out 1/2 turn.

Both screws should be at roughly the same position, so once your figure out where one should be set, use that as a guide. The fact that one screw has no effect on idle speed/quality is puzzling. Have you tried blowing thru the idle circuits with air or carb cleaner?

Glenn Morgan: 66 GT V-Burgundy Fastback 351w+toploader+9 in. TracLoc. Started out as a rusted-out Chicago-area crusher. After sacrificing a solid 66 coupe for its sheetmetal sub-assemblies, I have one solid (and expensive) work in progress!
 

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Discussion Starter #4
I'm using the dual plane Performer 289 manifold.

'68 Coupe, 289, C4, 3.40 gears, GT-40P heads, TCI Streetfighter stall convertor.
 

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Discussion Starter #5
I sprayed carb cleaner through screw ports and liquid sprayed through the idle circuit on both sides. I'll try the air and see what happens.

'68 Coupe, 289, C4, 3.40 gears, GT-40P heads, TCI Streetfighter stall convertor.
 
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