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1975 johnson 20 hp no spark

L

LHaley

New member
I recently picked up a 20 hp johnson, and with a bit of research and the model number, traced the year back to 1975. it had mice living in it over the winter, so there is some wire exposure from the mice chewing through the rubber surrounding the center of the wire, but nothing is chewed through that i can see. the problem is that there is no spark in either cylinder, as far as i can tell. i do not have a spark tester, i am simply holding the plug to the crankcase as a ground and turning the engine over. I find it hard to believe that both coils would go bad, as the guy i got this from said it was running last year, but i am not too familiar with outboards. could it be the points? or possibly the kill switch wiring? I am not sure what to try and do next
 
Allways start with the obvious first. Electric start or pull start?[/QUOTE]
It has a pullstart, but i think it can be electric start too. it has a spot for some sort of plug next to the fuel connector
 
Its probably an older motor because I don't think that Johnson made a 20 in 1975. Both motors used points, however.....and that could be your problem if the kill switch isn't shorted out. If its a 1975 the "exciter" coil could also fail but not likely just from sitting.....the mice can't get under the flywheel either to do any damage.
 
????-----------OMC did market the 20 hp models in Canada for many years !!!!--------Start with removing the flywheel and cleaning the points.-----Both sets must be absolutely clean.-------The plug next to the fuel connecter may well be for " AC lighting " to run the boat lights.=======Pictures help.
 
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Sorry, maybe I'm having a senior moment, but I think the last year on this planet for to 20's was '73 then picked up again in '80 or '81......I gotta check again. You guys are great fun.
 
20150909_185235.jpg20150909_185247.jpg20150909_185337.jpg20150909_185345.jpg20150909_185404.jpg

here is the beauty itself. as you can see, there is a little wire damage. the coils look rough, but there are no cracks
 
Yes now I remember the 20's and they were almost all the same parts. I looked and I even have a parts motor in my shop that may be Belium made. I think Canada sold the 25's through this time frame too and that is what we bought for our camps. They just don't idle as smooth and we had complaints that they were a bit too fast when trolling for lake trout. We went back to 15's and on the bigger boats we ran 2 15's side by side, then they had an extra motor in case something went wrong. The 15's are noticeably better on fuel.
 
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