Rebuilding '75 Johnson 15hp pull start that I have never seen run. Rebuilt ignition and got good spark and decided to check compression before putting everything back together. only got 40 psi on both cylinders. Heard should be around 90-100. Is there any difference between the compression reading for a manual start vice what you can get with an electric start (no comments about wimpy arms, please.) Haven't tried to start it yet because of crack in the fuel filter.