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I wish that I knew how the spark timing is done for the two cylinders and if one could be correct and the other be wrong.
It I'm sorry to step in. I'm trying to post a new post question on replacing Reed valves for an 88 Evinrude 40 horse
The flywheel spins.-----The magnets sweep by the charge coil and sensor coil ( 1 of each ) that times the spark.-----So answer this very important question.-------Does the spark jump a gap of 7/16" ( 12 mm ) yes , no or no idea why that is important.----Timing can not be different between the 2 cylinders.
You are confused and struggling with a simple motor.--.------If you answer questions you will get somewhere and make progress.----Once more, does spark jump a gap of 7/16" on both leads , yes or no ????
Buy a simple spark test tool or make one.------Glue 2 pieces of wire on a piece of carboard with a gap of 7/16" between them.------Now attach one end to the motor block ( ground ) and stick the other end in a spark plug boot.----Crank over the motor and observe spark at the gap.
Buy a simple spark test tool or make one.------Glue 2 pieces of wire on a piece of carboard with a gap of 7/16" between them.------Now attach one end to the motor block ( ground ) and stick the other end in a spark plug boot.----Crank over the motor and observe spark at the gap.
Let's see what we can do from here, first the plugs you described are equivalent but two different brands, second unless racerone can suggest something else I would check the sealing of the reed valves next. Take any screen off the front of the carb and put a piece of paper right up against the inlet of the carb. Now turn the engine over and see if the paper is drawn into the carb which is what should happen, if it's blown out away from the mouth of the carb then the reeds aren't sealing.