I just picked up a 1979 Evinrude 55 hp outboard. I kinda took a chance on this motor, I got it fairly cheap because it's only running on one cylinder. The seller threw some parts at it (new ignition coils, spark plugs, used cdi box) and then gave up. It apparently runs on both cylinders once it's warmed up, but I haven't gotten that far and I didn't want to run it as it is. Pulling the upper spark plug wire off makes no difference, but pulling the lower one off stalls out the engine.
I thought it might be dirty carbs so I took both carbs apart and rebuilt them with genuine Evinrude kits. Cleaned and blew compressed air through all the passageways, adjusted float levels, etc, no difference. It has lots of compression (140 psi, 145psi), lots of spark (bright blue sparks jump across 7/16" on my spark tester). I removed the reed valves and didn't see any light shining through them. With the engine running I tried to spray carb cleaner under the flywheel to check for a leaking crankcase seal and I didn't notice the idle speed change, although I'm not sure if I'm getting it up in there far enough.
Am I missing anything? Is there anything else I should be checking? I've been an auto mechanic for 25+ years, but I'm fairly new to 2-strokes. It's pretty humbling, lol.
I thought it might be dirty carbs so I took both carbs apart and rebuilt them with genuine Evinrude kits. Cleaned and blew compressed air through all the passageways, adjusted float levels, etc, no difference. It has lots of compression (140 psi, 145psi), lots of spark (bright blue sparks jump across 7/16" on my spark tester). I removed the reed valves and didn't see any light shining through them. With the engine running I tried to spray carb cleaner under the flywheel to check for a leaking crankcase seal and I didn't notice the idle speed change, although I'm not sure if I'm getting it up in there far enough.
Am I missing anything? Is there anything else I should be checking? I've been an auto mechanic for 25+ years, but I'm fairly new to 2-strokes. It's pretty humbling, lol.
