Need Carb Help!!

[jkc302]

It seems to run a little better at idle when it's warm. It runs fine while driving, under acceleration and all. The butterfly is open all the way while running.

I forgot to mention that the idle mixture screw it way out, almost all the way it seems. Also, I set the idle while in park. I think it is supposed to be done while in drive?

Jon

 

[jkc302]

Bump - Hello?? Bump.......

 

[MercuryMarc]

It seems to run a little better at idle when it's warm. It runs fine while driving, under acceleration and all. The butterfly is open all the way while running.
I forgot to mention that the idle mixture screw it way out, almost all the way it seems.

I am not an expert but I think you have a large vacuum leak at idle, which is why you have to have the idle mixture screw all the way out. I think the usual range is 1.5-2.5 turns out (not certain though).

So you can spray carb cleaner around the base of the carb while it is running and if there is an RPM change then that's where your leak is. I have found some leaks by using a rubber hose and putting one end near the engine and the other near my ear.

Good luck!

Marc

 

[ludwig]

It runs better when it is warm because some of the holes close up when the metal expands and it cuts down on the size of the leaks. Check the vacuum with a vacuum gauge. You should be running in excess of 18*. That is to say that 18* is your functional minimum. If you are running less than that with a stock or near stock engine you have a leak problem. A vac gauge only costs $10 to $15. Use a manifold vac port.

 

[jkc302]

I checked for vaccuum leaks. Didn't seem to have any. I tightened the carb a bit and cut off all the ends of the hoses as some were a bit loose. I reset the idle and it seems a little better but not much. It still has a rough idle while in park and in gear. Other than that it drives fine.

I just would like the idle to be smoother. I'm sure it can be but I'm out of ideas.

Help!!

Jon

 

[MPGmustang]

what's the vacum pulling at Idle???

here's what I would try.
adjust A/F screw to run the fastest you can get, (make sure engine is warmed completely up)
Change Idle screw to 700rpm (in gear)
find a hill and floor the pedal going up the hill, if no ping then advance the timing 1*, repeat until u ping
once you ping back off 2*
reset idle to 700rpm (while it's in gear)

I know the ford manual say's 500rpm for manual trannies and auto trannies (note auto trans is in gear with someone holding brake) but I've only found best idle at 700+ no more than 850rpm

for vacum leaks, you can try to find them with a hose to your ear, and "probe around", you can amplify the leak sound if you hold a hand over the carb barrel (choking it to almost death). you might need an extra hand or two. check the carb plate gaskets, above and below the carb plate. is the PCV still working? I've noticed a tramendous improvment when I replaced mine, but that was mostly sound.

Good Luck!
Richard