Posted by David Sherman on Wednesday, December 06, 2006 at 0:49AM :
In Reply to: My New (OLD) M-37 posted by doug on Wednesday, December 06, 2006 at 0:24AM :
If it was mine, I'd first run a wire straight from the battery to the coil and see if I get spark then. If so, check the wiring, switches, etc. If not, check for spark at the coil output directly. If spark there, but not at the plug, trouble is in distributor or HV wires. If no spark at coil output even with batt connected straight to coil input, check the points and conductivity of coil to make sure it's not open or has a bad connection. Easiest way to do both is put ohmmeter from batt terminal of coil to ground. When points close, resistance should be low, when points open, should read infinite. Not sure if you still have a military ignition system, but if it's been civilianized a long time ago the "black tubes that look like fusible links" might be radio interference suppressors. I have some old ones like that which I think were made to mount atop the spark plugs. They could certainly open up and cause a lack of spark too. If that's the case, you'll still have spark at the coil output.
Since it ran for a while, I'd tend not to suspect the points since they usually cause it not to start after the truck has set for a long time with the points open. A plug wire or resistor is also unlikely since if it ran good at one time and then completely quit, they'd all have to have failed at once, which is unlikely. If only one or two failed, it would just run rough.
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