Farmall super m backfires

Jack Stanley · Aug 26, 2016

Hi all, I recently bought a super m it runs and drives really well. However when I'm running it wide open or close and slow it back down it backfires 3 or 4 times usually. I also noticed the carb gets icy right where it bolts to the manifold and the muffler seems to get too hot to me.any suggestions? One more question. When going up a hill or whenever it's under a load there is a tapping sound coming from the engine when it's not under a load it runs smooth as silk. Valves out of adjustment?? Thanks!

dzc3 · Aug 26, 2016

Might be running too lean.

glennster · Aug 26, 2016

The backfire and hot exhaust sound like a timing issue. Retarded timimg will cause that, also check the centrifugal advance to see if sticking. Pop off distributor cap and give the rotor a flick and see if it returns. If not, its prolly rusted up.

leroy in ne · Aug 26, 2016

sounds normal to me, used to see how many back fires I could get coming down the hill from the south field. 1/4 mile wide open in fifth and slam the throttle shut. bang bang, 13 years old and great fun. also plowing at night 3rd gear with 2-14's about 8" deep and see the muffler glowing dull red in the middle. later lit many a cigarette on manifold or muffler when my matches got sweat soaked.

Charlie M · Aug 26, 2016

Your tapping sound could be a rod bent that opens the valves. I had 2 like that on my M.

old · Aug 26, 2016

Carb icing is normal and ALL carbs to it just many you do not notice.
Back fire could mean it is running to rich so when you let off on the throttle gas pools till it hit a hot spot then ignites with a bang

RogerinIowa · Aug 26, 2016

The tapping sound could be detonation (pinging). What are you running for fuel octane. Where is your timing set?

Icing of carb is normal.

rustred · Aug 26, 2016

best to check the timing and even set the carb after timing is set, not before.
the icy carb is normal as that is the venturi effect. when the air is speeded up going through the venturi it is cooled down and thats what you get.
depends what you mean by tapping sound... as it can be a cracked manifold also. very good idea to set the valves... .017 hot. that is one thing i always do , as the valve seats wear the clearance is decreased. running with tight valves will result in a burnt valve.and you know the rest of the story.

Jack Stanley · Aug 27, 2016

Thank y'all very much for your help! I am going to check the timing and adjust the valves and see what that does for her. Thanks again

Farmall super m backfires

Jack Stanley

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dzc3

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glennster

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leroy in ne

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Charlie M

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old

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RogerinIowa

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rustred

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Jack Stanley

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