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The motor idles and runs great. But when I slow down I get a SMALL
Back fire. Things I have done to correct this.
1-cleaned idle jets
2-replaced intake metal gasket and torque to 12 ft lbs.
3-replaced plugs
4-replaced plug wires
5-replaced rotor
6-replaced distributor cap
7-adjusted values and rechecked
Thanks for the help
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The motor idles and runs great. But when I slow down I get a SMALL
Back fire. Things I have done to correct this.
1-cleaned idle jets
2-replaced intake metal gasket and torque to 12 ft lbs.
3-replaced plugs
4-replaced plug wires
5-replaced rotor
6-replaced distributor cap
7-adjusted values and rechecked
Thanks for the help
Yes, most of the time it is a small exhaust leak but you will hear thiis at idle as a erratic pop but sometimes and especially lately it is bad gas leaving deposits on the valves, set the valves loose at 8 and run a couple of tanks of gas with fuel system cleaner. Also you can use the Italian tune-up method of running in third at 4500 RPM for a few miles. These things will help to clear deposits off of the valves.
Is this a small "burble" or bonafide "backfire"?
Did this occur after something was recently altered?
It's probably just a little richness during decel, if its just
a "burble" I say enjoy it. If it's a "backfire", I would guess
[go along with] the rich idle circuit theory. Did you recently alter
the exhaust? Good luck.
On the subject of Italian tune ups.....

Think you may have dirt in a carb jet ? Run it up the 4500 RPM and witt he air cleaner off, put your hand flat down on the top of the car ( shop rag recommeded ) choking off the air supply till the engine almost quits ....run it back up to 4500 RPM's and repeat this a few time ...you'll be surprised at how well this can cure the problem !

Alan M
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