Johnson 20 hp Seahorse

I purchased a 20 hp Johnson Seahorse on a boat. The lower unit has oil in it and I have spark on the top cylinder. The bottom cylinder has no spark. The carb smells like lacquer. I can rebuild it myself. My Problem is I have no Model number on my motor that I can find. I have looked everywhere. I did find a number on between the cylinders that reads E3421839. To order the right parts I need the model number. It appears to be 1970 to 1973. ANY HELP.

Re: Johnson 20 hp Seahorse

Clean and kit carb and replace the 5/32" fuel line from fuel pump to carb. If your motor doesn't have two coils mounted near the head, they're under the flywheel w/pointsets. If it has external coils near head, and no CD box, you have points and a charge coil under the flywheel. In either event, check coils for cracks or burn holes where it arc'd out. Confirm coil ground wires are tight. File the point faces up shiny and reset to .020", or just replace points/condensers (kit is about $20). If your motor has a CD box it has no points. In that event, swap coils and see if the no spark wire follows the coil.. If it does, that coil is bad or ungrounded. Hope this helps, and good luck!

Re: Johnson 20 hp Seahorse

rhendershot said:

I purchased a 20 hp Johnson Seahorse on a boat. The lower unit has oil in it and I have spark on the top cylinder. The bottom cylinder has no spark. The carb smells like lacquer. I can rebuild it myself. My Problem is I have no Model number on my motor that I can find. I have looked everywhere. I did find a number on between the cylinders that reads E3421839. To order the right parts I need the model number. It appears to be 1970 to 1973. ANY HELP.

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The good news is the 1969-1990 20hp models use the same carb kit. Avaliable here on iBoats.