Posted by J. Veitti [69.144.190.102] on Wednesday, June 16, 2010 at 22:19:53 :
I visit here a lot and have a few PWs but my question today regards a Ford 8N tractor. You guys are really good at trouble shooting and the Ford engine is not too different from a Dodge 6-so:
I had the engine rebuilt a few years ago. I have never used the tractor much and it has always been weak and has a persistent miss. It fouls the rear two plugs with black soot almost immediately after changing plugs. So I decided to fix it once and for all.
I installed a new carb-no change. Put in new plugs, wires, dist. cap, rotor, points and condenser. Every thing but the coil. No improvement.
Checked the compression and it is really even at 110-117 psi across all four cylinders. Ford book says over 90# is good.
So what now?? All I can think of is replace the coil. It is the original 6 volt coil but I have converted the tractor to 12 volt and am running a resister to drop voltage to the coil. One clue is that if I lift the plug lead off the plug while running, and make the spark jump a big gap to the plug, the engine speed will pick up and the miss is better. This is an old trick for weak spark situations but how do I use this information??
Ideas appreciated!!
John In Wyo
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