1972 85 HP Johnson Outboard - Please Help

[Remington270]

Hello,

I am in need of some help, if anyone could please assist me it would be greatly appreciated. I am graduate student at a university and am doing a study on zooplankton within various southern alberta lakes. I recently just got donated a boat and a motor. The motor is as mentioned above a 1972 85 HP johnson, however, the motor sat for a few years and the whole bottom unit was filled with water and all the gears are wrecked. I was wondering if anyone knew of a cheap place to purchase a used or a rebuilt one, I have extensively searched on Ebay and Kiijii, however, I am skeptical as to what I am purchasing. In addition I took the bottom end off, and tested the compression in all the cylinders, they are 135, 135, 145 and 125. When I try to fire the motor up however, I cannot get spark to the plugs yet when I turn the key off it backfires. I disabled the controls and jumped the motor with a new battery and the same thing happens. I was wondering if anyone knew any solutions, I read about the powerpacks and I am hoping it is not that, as they are not relatively cheap; being a student I do not have alot of disposable cash. Is there any simple/cheap way to check if it is the powerpack or is there another problem that is common in these motor ignition systems that may be causing this?

Thank you for your time in reading this and again any help would be much appreciated.

Cheers.

 

[Duke 3D]

Re: 1972 85 HP Johnson Outboard - Please Help

You need to check each spark plug for spark. Do one at a time, remove the plug, leave attached to the wire, use insulated pliars to hold the threads next to the engine while cranking. If two are getting spark and two are not getting spark it would indicate the power pack as suspect as two separate sections feed two cylinders. If no cylinder is getting spark would suspect the ground wire from the ignition is shorted out. When you turn off the key the ignition takes spark to ground to stop the engine, but if you get a short in the wire or ignition switch it will keep you from getting any spark. To check this you can disconnect the ignition wires back at the motor end. There's also a chance one or more of the coils themselves are bad. They tend to crack. You'll see black marks if spark is escaping to ground. The ground wire coming off the coil MUST be grounded. There is a tendency for the spark plug wires to short circuit to ground where metal straps hold them down. Remove any of these and inspect the wire for a round black burnt pinhole. Lastly, there are boat junkyards that sell used parts half of new. If the one they sell you isn't any good they'll usually trade it and all you've lost is some time. Good luck.