Spark Problem

[minibike]

We are having problems with the spark on a buddy of mines 72 truck. It's a big block, with HEI. Distributer has enough spark to make a pale yellow spark if a screwdriver is held in the spark plug boot and held close to ground, but not with the plug.

With a plug (grounded) it will not spark, and when a timing light is connected to the plug wire, it will not even have enough spark to kick off the timing light.

Now...the interesting part. Take the distributer out, clamp a ground on the vacuum advance, and put the power wire on...

It sparks fine when you rotate the gear.

Put it back in the engine, clamp the ground to it...same setup...nothing.

Any ideas here? We are really having difficulty with it.

Steve,

We got the suggestion to clean the area where the dist seat, and we will try that next, but we did have a jumper cable going from the battery to the negative on the battery.

HELP!!!!