Hi All, Have a question about my 1973 Ford Gran Torino with the 351 v-2 engine. I have a pretty significant surge at idle. When I come to a stop light it will sound like it is going to stall and then surge up and down. Never stalls out though. If I take my foot off the brake it will lunge a little forward on each surge. I don't seem to have a vacuum leak but have not put a gauge on it yet. Just poked around with some flammable spray. Could it be clogged idle circuit in the carb or something less complicated? Just want to rule out other possibilities before I tear into the carb. Any Advice is appreciated.
Check the valve on your power brake booster. I had the same trouble and was going nuts trying to find the vacuum leak. I changed the valve and fixed it just like that.
Could be a clogged idle circuit, surging is generally the result of a lean condition. Count the turns in until the idle screws are seated then remove them and flush out with some aerosol carb cleaner, might get lucky.
If it's the idle circiut, CHOKE IT! Remove the air cleaner, rev it by hand to about 4 grand, and put your hand over it 'til it almost dies, and remove your hand. 3-4 times usually fixes things!
Thanks guys! Still dealing with this so when I get some time to work on my car I will try these tips. Any of you know if the Rebuild on these carbs is pretty easy? I have done a few rebuilds so will go down that road if I have to. Seems to be running great other than this surge thing at idle.
Those autolite carbs are easy to rebuild but they are prone to clogging in the idol circuts like all the veterans here say. Without boiling out the carb plates, it's not something you can stick a pipe cleaner through and clear. By closing the choke, the main flow of air is shut off and the vacuum in the carb forces the fuel to unclog the passages. I had an old 57 ford that I had to do this a couple times a week due to a bad tank that I couldn't afford to fix. You could try revving the engine and then letting off the throttle while holding the choke closed on the carb until it almost kills the engine. Do this a couple of times and see if it doesn't help. Dave
Coulda sworn I said that in #5 - without using the choke and maybe messing up the linkage or settings! Was taught by my Dad, a 50 yr Ford Mechanic!!
and like i said on another post always check your vacuum reserve can for pinholes. i always do when i do a tune up on my ford
