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Discussion Starter · #1 ·
1951 john deere b, good compression, just rebuilt carb, new plugs,
at idle sounds and runs good but to give it gas it starts mis firing and black smoke and hardly no power, timings ok, i think i see a crack in dist cap close to middle, any ideas will be helpful. also checked valves,,,,,,,
thanks
 

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Our A gave me trouble a whole year! did the same thing and even stalled when i hit bumps and chugged black smoke, it was a plugged air cleaner! rodents made a nest inside it and it was blocked up tight. Later in the year I had a cracked rotor too and did something similar because it was moving around on the post
 

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Hate to note the obvious, but do you have the correct plug wire going to the correct plug? I would go ahead and change the dist. cap also. Just because the plugs are new, doesn't mean they are good. I had new ones do something very similar. Changed them again and the problem was solved.
 

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johndeerefan said:
Hate to note the obvious, but do you have the correct plug wire going to the correct plug? I would go ahead and change the dist. cap also. Just because the plugs are new, doesn't mean they are good. I had new ones do something very similar. Changed them again and the problem was solved.
Yep did that before :D
 

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Usually, black smoke is an indicator of arich conditon, as in getting too much fuel. I think maybe the carb is looking for the other 2 cylinders!!! (Sorry, couldnt resisit!) The cap problem would cause skipping or misfiring, and you say as I gather it idles good, so yes the cap could be the culprit, but Id lean more towards a fuel problem simply because of the black smoke.
 

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yep.. black smoke is way rich. if it does this on throttle up.. id check air cleaner for restriction and choke to make sure the mechanism is working.. especially if it runs good at idle..
 

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Discussion Starter · #7 ·
dist cap and new plug wires straighten everything out, she now runs and starts great,
cant wait till 4th july parade now,,,,,,,,,,,,,,,,,
 
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