Re: 1970 Merc 7,5 no start
If it has the red plastic cover,then it has had the donut replaced at some point. There were two different versions of the low-tension magneto. One with a solid state green donut, about 5-inches in diameter, and the other had the red plastic housing. Inside the housing are two sets of points. Make sure they're clean and gapped at .020. The manual says it's not critical that they be clean because of the voltage involved, but I've had no-spark motors in the shop that have gotten spark with new points... It's worth a shot...<br />- Scott