15-hp evinrude outboard spark problem

[motorshop]

working on a 1975/15-HP evinrude, i have an intermitant spark problem and the last thing i did was remove points and clean and file, have been milking these points numerous times before by just filing them, then bench tested and had good spark, took out on water and after 15 minuets of good running and getting it warm it started to bog and seamed to only run on 1 cyl, so put back on bench and checked spark plugs they are new but 1 was not firing, checked for spark again and 1 seamed weaker than the other, i have had this problem many times, trying to figure if it is coils,magneto, or should i just try new set of points,obviously trying not to spend money, but does it sound like coils getting hot and failing or mag, or just points and condensers, looked at points before with magnifying glass and i think could be condenser problem,any input would be greatly appreciated,thanks,JRD.

 

[Rick.]

Re: 15-hp evinrude outboard spark problem

You could try swapping components one cylinder to the other to see what combination gives you the best spark/worst spark. Or you could get new coils, points and condensers and hope that solves the issues. On close inspection do you see any cracks on the coils? Many is the time coils start and fail as the get warm. Those parts are 35 plus years if never changed. Best of luck. Rick.

 

[motorshop]

Re: 15-hp evinrude outboard spark problem

thanks rick, under further examination 1 coil has hairline crack in it,happens to be the one that looks like it stopped fireing, going to put new coils and tune -up kit on it,thanks again,JRD.

 

[Rick.]

Re: 15-hp evinrude outboard spark problem

A wise choice IMO. Hate these internal combustion engines when they fail so it's worth a little extra effort and expense to have trouble free trips. Rick.