I have replace the plugs , plug wires , new carb gaskets , reset timing , installed electric fuel booster pump and still it backfires , points have less than 2k miles on them
the is in a 1983 119 - the timing is set at 3 degrees atdc
I now suspect that either the timing is off or its the dist. any suggestions ??
Mixture's not too weak? Timing's been set dynamically or statically?
What state were the old plugs in?
If it's only been used on short journeys for a long time, it may need a decoke, especially if it's using oil. Mine needs a good blat for twenty miles or so every few months, or it starts backfiring on the overrun.
If I remember correctly, the 3 degree after tdc setting on the pulley is for 70 octane petrol, but mine's quite a bit older than yours, and has the 7:1 compression ratio engine. It likes about 7 degrees before tdc for 95 octane petrol. Someone will probably remember the right figures now I've made a fool of myself....
3 degrees after? surely it wants about 6 degrees before. Have you changed the condenser? or taken it out of the circuit due to wiring the points in wrong? That happens a lot, easily done.
My 2.5 petrol would not run well when I set the ignition timing properly, I had to resort to the old timing by ear method and it's way different from what the manual says. Better petrol?
Thanks to Bob Hobden : reset timing by ear - pulls much better but still has the lean / backfire problem
the 2 barrel weber has an electric kill switch does it fail causing this condition ? can it be removed and blocked off ?
A small leak at the exhaust manifold to downpipe flange will admit air on over-run and cause backfiring.
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