1963 Ford Thunderbird POPPING NOISE

NEILWILLIS

MEMBER
1963 FORD THUNDERBIRD
80,000 MILES

I have a standard Holly 4Bll carburettor, the engine would NOT run slow so Ive set the timing at 10 degrees ( correct) and backed of the speed srew until it doesn't touch, then still no good so I backed off the CHOKE screw which allowed it to run slow, the engine runs relatively smooth but now has NO vacuum until I accelerate it, and a random POPPING noise. All plugs are ok the two fuel screws don't seem to make much difference either before or after I adjusted the speed. When I accelerate the engine ( still in the garage0 the vacuum appears good at 22-24 and NO POPPING at that speed. But when I let it idle the popping returns
Neil

5 Replies

WRENCHTECH

MECHANIC
20,757 POSTS

With the engine off look down the carb and slowly open the throttle and see if you have a steady stream from the accelerator pump.

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Wednesday, July 3rd, 2013 AT 6:48 AM

DOCHAGERTY

MECHANIC
9,601 POSTS

And watch out for that backfire, cover your face

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Wednesday, July 3rd, 2013 AT 7:23 AM

WRENCHTECH

MECHANIC
20,757 POSTS

I don't think he's going to see any backfire with the engine OFF (as instructed) Dr.

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Wednesday, July 3rd, 2013 AT 7:46 AM

NEILWILLIS

MEMBER
6 POSTS

Hello
Ive been doing this for 50 years and DU Ive connected the vacuum take off to the carburettor to distributor line. Anyway now its direct to the manifold the vacuum appears to be 16 Ive got the speed down by backing off the choke adjustment nut to 600rpm at idle not in gear ( ok)? The two fuel screws still don't do anything, Ive checked for vacuum leaks with a spray oil, all ok.
So Timing at 10 Degree, speed at 600, vacuum at 16 but goes up to 22 when revved but I still cant adjust the fuel in any way and the POPPING is less now but occasionally still there.
At the rear of the engine is a what appears as a vacuum take off, going into a 2" long bolt which I suspect is some sort of filter or valve. Anyone know what this is?
Thanks again to the three of you who have helped.
Neil London UK

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Wednesday, July 3rd, 2013 AT 8:47 AM

WRENCHTECH