Carburetor - 66 fastback

Willnaz · 01-29-2001, 12:46 PM

I have a 1966 fastback 2+2 w/a 289, 2 barrel holley.

This is the 2nd carb i have put on. It keeps going bad....I have not ruled out the fact that I have just run into bad luck but am getting tired.

I was wondering if there are any other people with the follwoing problem:

After replacing the carb (both times now) and getting a complete tune-up. The car starts running rough and spuddering/choking/losing power and ultimately starting to backfire.....then the muffler gets blown out due to the backfiring....I am at a loss. I spoke with the carb rebuilder and he said that is is not likely to bethe carburetor. Anyone have any clues.....any informatin would be greatly appreciated.

Thank you all for your time.

William

------------------
William
plur@uswest.net

Clark Rodgers · 01-29-2001, 08:42 PM

William,
It does sound like an ignition problem usually caused by a timing issue. Have you ever checked the timing after the carb installation? Everytime I have seen backfires it's because there is a spark where there should'nt be, the carb just delivers the gas.

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69 351W Sportsroof deluxe

thunderbolt · 01-30-2001, 11:46 AM

I am in agreement with Clark. Had that Holley, and while Holleys are known to be tempremental, mine worked great all the time. But backfires will blow out the power valve which will need to be replaced. I would start with a new cap and rotor. A cracked rotor builds up carbon deposits and starts arcing where it shouldn't. Give your ignition system a tune up and see what happens.

01-29-2001, 12:46 PM	#1
Willnaz Registered Member Join Date: Jan 2001 Location: Phoenix, AZ USA Posts: 1	Carburetor - 66 fastback I have a 1966 fastback 2+2 w/a 289, 2 barrel holley. This is the 2nd carb i have put on. It keeps going bad....I have not ruled out the fact that I have just run into bad luck but am getting tired. I was wondering if there are any other people with the follwoing problem: After replacing the carb (both times now) and getting a complete tune-up. The car starts running rough and spuddering/choking/losing power and ultimately starting to backfire.....then the muffler gets blown out due to the backfiring....I am at a loss. I spoke with the carb rebuilder and he said that is is not likely to bethe carburetor. Anyone have any clues.....any informatin would be greatly appreciated. Thank you all for your time. William ------------------ William plur@uswest.net

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01-29-2001, 08:42 PM	#2
Clark Rodgers Registered Member Join Date: May 1999 Location: Rowlett,Texas Posts: 306	William, It does sound like an ignition problem usually caused by a timing issue. Have you ever checked the timing after the carb installation? Everytime I have seen backfires it's because there is a spark where there should'nt be, the carb just delivers the gas. ------------------ 69 351W Sportsroof deluxe

01-30-2001, 11:46 AM	#3
thunderbolt Registered Member Join Date: Oct 1998 Location: Houston, TX, USA Posts: 380	I am in agreement with Clark. Had that Holley, and while Holleys are known to be tempremental, mine worked great all the time. But backfires will blow out the power valve which will need to be replaced. I would start with a new cap and rotor. A cracked rotor builds up carbon deposits and starts arcing where it shouldn't. Give your ignition system a tune up and see what happens.