idle issues
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Tuned
Joined: Jun 2008
Posts: 412
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From: sc
idle issues
well guys here's what my truck is doing the timing is set at 10 degrees i have the idle at 600rpm in park its a 351w mild cam 625 street demon carb when i'm driving and i get to a stop light it tends to want to act like it stalling. should i bump the timing up to 12 -14 degrees also when i go to shut it off it wants to keep running....... what do you guys think?
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Don't advance the timing. Where do you have the vacuum advance connected? If you are using manifold vacuum put it to ported vacuum for a test. And, is the 600 RPM when in gear or neutral? If you can, drop it down a bit - that'll help with the run-on.
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Tuned
Joined: Jun 2008
Posts: 412
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From: sc
everything is connected properly vacuum advance is to the front of the carb ported. gotcha on the idle speed i been up and down on that one i just bumped it up the other day doing some testing..i'm not the best carb guy & i really need this carb dialed in so i might take it in to a local shop cause it is running rich but it doesn't have a cat on it either
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Just got the PM, and it is late for a call. But, to adjust the idle mix correctly you need either a vacuum gauge or a tach. However, you can try it w/o either by listening to the engine.
Turn one screw in 1/4 turn. If the idle speed drops you went the wrong way, so turn it out the 1/4 turn plus another. If the idle speed picks up turn the other screw out 1/4 turn. Keep alternating back and forth until the idle speed drops, and then turn back in until you have max RPM. Open both screws up 1/8 turn from there, and adjust your idle speed back to 600 in gear.
You are adjusting for max RPM, which is the same as max vacuum. But you want both screws open the same, so make sure you are starting with them open the same. One way is to close them gently, open them up 2 turns, and then adjust from there.
Turn one screw in 1/4 turn. If the idle speed drops you went the wrong way, so turn it out the 1/4 turn plus another. If the idle speed picks up turn the other screw out 1/4 turn. Keep alternating back and forth until the idle speed drops, and then turn back in until you have max RPM. Open both screws up 1/8 turn from there, and adjust your idle speed back to 600 in gear.
You are adjusting for max RPM, which is the same as max vacuum. But you want both screws open the same, so make sure you are starting with them open the same. One way is to close them gently, open them up 2 turns, and then adjust from there.
Moderator
Joined: Jan 2001
Posts: 56,949
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From: Virginia
Even though you have the distributor on ported vacuum, with the engine idling I would pull that line off. If the rpms change put your finger over the port on the carb. If it has a slight suction to it something's not right, usually the carb throttle is open too much at idle. Just something to double check.
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