1986 Mercury 20 HP - Intermittent Spark

I have a 1986 Mercury 20 hp (Serial # 0B152472) tiller w/electric start that has an intermittent spark problem. At times, it runs just fine…starts right up, idles nice and good, smooth acceleration easy restarting both warm and cold. At other times, it will start with a little hesitation on full choke and three primes, run up to a couple minutes, back off the choke to warm it up and then it will die (not quite fully warmed up). Minutes of cranking the starter will sometimes get the motor to restart again, but the engine seems to runs rougher than normal and usually dies. (I have found that if I put it in gear, it will usually stay running until I shut it off, then it will not start again). I’ve got new plugs, and in checking all connections after the problem asserted itself again this morning, I checked for spark. No spark! I have checked for loose electrical connections and all is tight. Any ideas as to the problem and how I can verify the problem? (Please remember I am a novice to outboards, without a manual, however, I have and know how to use a digital multimeter. I have read through the forum but have not seen any postings that seem to resemble my outboard’s problem.

Re: 1986 Mercury 20 HP - Intermittent Spark

So, noone has any ideas????

Re: 1986 Mercury 20 HP - Intermittent Spark

Have you replaced the ignition coil? The coil on an outboard is similar to an automobile. they are perculiar creatures. My suggestion would be to replace the coil and add fuel additive to the gas tank to keep the carb clean; thus keeping the choke clean.