OK so I just cleaned and adjusted the point and condenser to .o45" and it seemed to run good first pull I let it idle for 15 mins and it ran smoothly, then I went in and had dinner and came back out and went to start it it ran for about 20 seconds and conked out. After trying to start it for about 10 minutes I checked to see if they was a spark. I pulled the plug out and rested it on the block.I connected my drill to the crank and kicked her over, there was spark! At idle speed so I wound the speed up to say somewhere in the mid range maybe around 1600 rpm the a loss of spark. So I reduced the rims back down to idle speed and the spark RE appeared... what could this be? And what parts do I need to fix it? Cheers jason