motor will not run, unless sparkplugs are changed

Hi, I have a 1958 (so I was told) Evenrude electric starting motor (18 hp, I think). I don't know the model #, but the s/n # is 15922 50474. With new plugs it starts on the first try....and the whole day I'm out on the lake it runs and starts fine. But the next time I take it out it just will not start, unless I put in new spark plugs. Currently I am using Champion J6C plugs. I've noticed that the top plug has alot of build up around it, where as the bottom plug has almost no build up.

Re: motor will not run, unless sparkplugs are changed

I have a 59 50hp v4 and I have the same problem top 2 cylinders keep fouling bottom 2 clean as a whistle. Im looking into fuel issuses at the time because i seem to have good spark on all cylinders. I'll keep u posted.

Re: motor will not run, unless sparkplugs are changed

Hello.<br />You are right,it is a '58 18 horse.<br />The plugs you should use are champion J4C,not J6C.<br />That however is probably not the source of your problem.<br />If you run that engine at trolling speed for most of the day there will be built up of carbon and not only on the plugs but everywhere.<br />A 50 cent soft copper brush will clean your plugs and they will be as good as new ones.<br />For the rest you should try and decarb the engine.Go to a napa store and buy 1 bottle of seafoam and a spraycan of the same.Pour the bottle into your tank and decarb your engine with the spray.<br />At the end of your day on the lake,run the engine at w.o.t. for ten, fifteen minutes.<br />This should probably solve your problems.<br />Good luck.

Re: motor will not run, unless sparkplugs are changed

Martin...<br /><br />You may be experiencing a weak spark. Check the gap on the points, should be set at .020. And do you know just how old the points are? May be time to replace them along with the condensers. Also make sure the wiring is good with no bare spots that could be shorting. Look at the ignition coils also. Make sure they are not cracked. Cracks cause shorts to ground.<br /><br />Both sparks should be able to jump a 7/16 inch gap.<br /><br />Let us know what you find.

Re: motor will not run, unless sparkplugs are changed

^ Thanks alot guys. How often should I decarb? And a stupid question, but what does w.o.t. stand for?

Re: motor will not run, unless sparkplugs are changed

WOT = Wide open throttle<br /><br />c/6<br /><br />Hooty

Re: motor will not run, unless sparkplugs are changed

According to my Evinrude Model number list you have a 1957 model 18 hp. <br />Model numbers for that year (1957) are:<br />15020,15021,15922 and 15923.<br /> <br />The model number is Model:15922<br />The serial number is Serial:50474