ford 4000 ka-pow backfiring when cold

bob kuczynski · Oct 24, 2017

my old throne in the flesh...my 64 4000 gas 4cyl is acting up again.
new carb, new points, rotor, coil, plugs, good battery, good timing, new lines, new gas filter and an in line micro filter to boot.
starts right up.
give it 1 minute, dadaddada pow pow dadada da powpow. dies.
let it sit 1 minute.
starts right up.
same kapow. turn it off.
runs 2 minutes.
kakapow pow.
sit it.
starts....kracckle dadadada pow pow runs for 3 hours like a sweating horse perfectly.
neighbor said bad gas.
tried gas additives. heat, you name it.
high test too.
no change.

any clue?

Mike M · Oct 24, 2017

No mention of a new condenser ? I'd try a new one or if you did put a new one in find an old one and try it.

old · Oct 24, 2017

Fuel problem throw that in line filter as far away from that tractor as you can and leave it there forever. Or you have some, floating junk in the tank that gets sucked down and shuts off the fuel flow

Steve@Advance · Oct 24, 2017

Exhaust popping, fuel igniting in the exhaust system, is a symptom of intermittent ignition.

Check voltage to the coil with it running. Could be loosing power to the coil, bad ignition switch, loose connection. Could also be a failing coil, bad connection to the points, worn distributor bushing, bad points or condenser (even though new).

bob kuczynski · Oct 24, 2017

condenser is new. tried old one. same issue.
the primary filter is in the tank. must be crud. after sloshing around, it must break free and fall off. agree?

old · Oct 24, 2017

Yep good chance you need to drain and flush the tank. I ran into this type of thing on a friends Ford 4600 diesel and found the stand pipe on the sediment bowl assembly was missing so it would run for a few minutes plowing and such then died due to lack of fuel from junk in the tank. Replaced the sediment bowl assembly with a new one with stand pipe and problem went away

MarkB_MI · Oct 24, 2017

By "backfire" I assume you mean an explosion through the exhaust. That would indicate ignition interruption rather than fuel starvation. Unburned fuel in the exhaust can ignite, particularly if the muffler is burned out or missing.

The ignition switches on these tractors are notorious for causing random ignition failures.

gene bender · Oct 24, 2017

If you think its a ruel problem open the drain on the carb and watch the flow. Other post said ign sw use a jumper from batt to the input side of the coil that could answer that problem. New condenser can also be the problem.

ford 4000 ka-pow backfiring when cold

bob kuczynski

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Mike M

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old

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Steve@Advance

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bob kuczynski

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old

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MarkB_MI

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gene bender

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