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Any ways to increase vacuum signal?
Running a Victor intake with a 1050 4500 and a 1 inch super sucker spacer on a 540. Vacuum signal at the carb is pretty weak at idle. Removing the spacer made a bit of an improvement but not enough. Maybe a 4 hole spacer might give the carb a better signal than no spacer? Any other ideas? Just trying to get the in gear idle a little better and not be overly rich to keep it running.
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Vacuum or air speed signal ?
Holley Reg, Ultra or some aftermarket mod shop ? 2 or 3 circuit ? New ? Have you found a sweet spot for initial timing ? This can really help. Hard to tune a carb if ignition is not correct. |
More timing at idle
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New Quick Fuel marine carb. 2 circuit, 4 corner idle. Idle mixture set on dyno and reset in the boat. Initial at 22°. Daytona box idle stabilization set for 850 rpm. Rpm in neutral 1100. Rpm in gear 600. 4-5 in. vacuum in gear. Tired of having it stall while trying not to hit things.
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Are you sure you don’t have a leak somewhere? |
Degrees the idle stabilization is adding?
Cam specs? Do you have a wide band AFR gauge? Describe your idle mixture adjusting procedure in the boat. |
Checked for leaks by spraying starting fluid. Idle stabilization is set to the max amount its capable of which is 20° Total timing 34°. Idle mixture initially set with vacuum gauge/ digital tach for highest readings and richened slightly after that when that proved unsatisfactory- but my vacuum port was in the spacer so now that its removed no more vacuum readings. Have a portable wideband but haven't utilized it yet. 663/241 646/246 on 112 cam.
Everything was done in stages. Tried with just carb tuning, then added idle stabilization then increased base timing. |
Did you adjust the idle mixture in gear or in neutral?
Do you have full mixture screw authority (can you snub the engine by turning the mixture screws in)? |
Engine is responsive to the mixture screws. Adjusted in neutral. Going to put some higher temp stats in to get some more heat. 140° is what's in it now.
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Adjust the idle mixture using the same method.....but in gear
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