I have a 1975 evinrude 25553b. I was up in voyaguers natl park over memorial day and it quit working. Ran great the firat day we were there but when we went to go back iut before su set it wouldnt fire. Luckily a house boat was able to tow us the 8 miles back to the launch. I cant seem to figure out the problem and get it to start. Ive replaced the points and condensors and set the points gap. I have spark and set the air gap on some testers to 1/4". The top cylinder spark does look to be weak and intermittent compared to the bottom cylinder. I do need to fine tune the timing as its about 1.5 degress off and the flywheel mark is just outside of the magneto marks. Ive done a compression test and have 92# on the top and 90# on the bottom. Are those numbers a bit low? I would think its enough to fire. I have fuel and rebuilt the carb last summer, could the float or something be stuck though? Any help or thoughts are greatly appreciated. Also, ive tried starting it with both the key and with the pull start with the harness from the battery and switch disconnected. The flywheel key is not sheared off either. Is it possible that the starter could be bad and causing a short?