my stang is idling to fast (1969 FB) I need advice

[road warr1or]

Hey all

So here my most recent poblem.

I Just put a Holley 4v 4150 single pump carb on my 302 cid engine. The carb was preset I guess to factory specs. I was albe to get the car to run enough to time the engine and I also attached a Tach to perfom the timing. (however, its probably wrong due to the high Idle speed) My spec says that the idle speed for the engine should be around 500 to 800 rpm. I can get it to idle below 1000 rpm. Last time I adjusted the fast idle and accelerator cable it was at 1200. I checked but I dont have any loose vacume lines it seems the more adjusting I do the worse it gets. even when I sut the car off and try to restart it it stalls out


Help!

 

[jcode68]

If you are sure you do not have a vac leak, then you should check the fuel pressure. If it is too high (you want it in the range of 5-7 psi) it could be delivering too much fuel, regardless of how your idle is set. You will need to put a guage on it to test the pressure.

 

[68shelby427]

it sounds like a vac leak

Id get a can of carb clean and start spraying around the base of the carb and thrrottle bushing. I know its not recommended but I have a lot of luck doubling up the carb base gasket to cure leaks.

 

[ForceFed70]

So you can't back off the idle speed adjustment screw anymore?

Definately check for a vacum leak. Also check/adjust the choke to make sure it's not the cause of your problems.

Also verify that your ignition timing is where it needs to be (usually around 12* base timing)

 

[road warr1or]

Ill check for a vacume leak. I used the factory settings out of the box and it idled fast. Then I adjusted the fast idle nut down to lower the idle speed. to around 800 rpm but the car would stall out when I put it in drive. I tried to adjust the throttle body but it just didnt work.

 

[BarnStang]

THe choke is a great place to check. Have had at least two cars in the last year with new Holleys that had the choke set screw wound in too far holding the butterflys open. THe choke weight will be down on the bottem step, but the screw is in too far. You can check this easy. With the car warmed up, you should be able to wiggle the weight up and down slightly. If this is the problem, it wil be tight with the set screw up tight against it. Back off the set screw (easier said than done!), then drop your idle and recheck the choke set screw again. Hopeflly that is the problem. Easy fix.

 

[BarnStang]

If you got it down to 800 and it stalls in drive, it would seem the timing needs to be advanced a tad. WHat do you mean by "adjusting" the throttle body?