Identify Johnson 3 HP

[JerryB4]

I have a Johnson 3HP Model # JW 20 B, Ser# B128407.<br />Would anyone know what year this motor is, and where I could get a coil for it ?<br />Thanks.

 

[Paul Moir]

Re: Identify Johnson 3 HP

That's a 1965 Johnson model JW-20. It makes it's 3hp at 4000 RPMs. It displacement is 5.28 cubic inches. (86.5 CCs)<br /><br />Coils are available everywhere, since they're the same as many OMC engines spanning 50's to 70's. Even NAPA can get you them. Their part number is 18-5181. That's an aftermarket part number, by the way. <br />You can also get them here and here pretty cheap.<br />Do yourself a favor and replace both if they're those old pink coils. If the other hasn't arced over or gotten wet yet, it will soon. Do yourself another favor and get 18-5006, the ignition tune up kit too. That's new points, condensors, etc.<br /><br />Those 3hp engines are indistrucible!

 

[JerryB4]

Re: Identify Johnson 3 HP

Paul, Thank You for the information, one more question, would you know the tune up specs as I am going to take your advise and get the two coils, points etc.<br />Jerry

 

[Paul Moir]

Re: Identify Johnson 3 HP

Sure. Gap the points at .020 maximum opening (rotate the crankshaft to find it). Spark plug gap is .030. Flywheel nut torque is between 40 and 45 ft/lbs. You'll probably need a "harmonic balancer puller" from an automotive tool store to remove the flywheel. Prying at the edges is a good way of wreaking the flywheel.<br />All this info and more can be found in the remarkably useful service manual, available for purchase here at iboats (or your local library to loan). Proceed without looking at one at your own peril!<br />Good luck!