1972 Johnson 100hp outboard

I have a chance to get a free '72 100hp. But, I have to take the boat and trailer too, which are junk. Id have to take it to the dump or something. Maybe sell the trailer. Its been sitting for at least 8-15 years out in the open. The cowl has always been on the motor. Supposedly ran when it was parked. Controls are there and functional.

Anyways, I would try to get it running again. Then, I would either sell it or try to put it on my boat. Right now I have a 85 Bayliner 16' with a 85hp Force. Runs just fine. But a few extra ponies would be nice!

So...my question is....is this project worth fooling with? Is the 100hp at all desirable? Do you think I could turn it over quick enough, especially if I get it running? Not familiar with this motor...its a 2 stroke right?

Lastly, would it be worth repowering my boat with it? 16' Bayliner, recenly rebuilt transom. My motor runs fine, but if I can squeeze in a few more horses that would be great.

Let me know what you think. Thanks!

Re: 1972 Johnson 100hp outboard

It's a small bore two stroke OMC crossflow model. It all depends on the powerhead compression and the lower unit. If the powerhead has good compression, that's a good sign. You will have to at least get the engine to turn over 250 rpm on the starter to check the compression. Then there's the lower unit. That model is the last year made with an electric shift lower unit. Now they are all mechanical shift. You need to make sure the gearcase will shift through the F-N-R gears from the control box. Those lowers aren't specifically bad (I ran that very same engine for 3 summers) but they are hard to get parts for anymore-and hard to find anyone that can work on them. I really liked my 72 100 engine. Ran flawlessly the whole time I had it. But that was many years ago. If you can get is running ok, it will absolutely outperform that Force-in all aspects.

Re: 1972 Johnson 100hp outboard

Thanks!

Doing a little reading on the Hydro Electric Shift lower units, I read they should always be in forward gear if no power is applied. The prop spun over freely as if in neutral. Is this a problem with the lower unit right off the bat?

Re: 1972 Johnson 100hp outboard

OK.....doing some more reading, I think this motor may be an electramatic, because that defaults to neutral, and now that I think about it I think I saw electramatic on the cowl. So this motor may be older? I should have taken some pictures!

Re: 1972 Johnson 100hp outboard

The year of the engine is found encoded in the engine's model number stamped on the serial plate. Post it.

Re: 1972 Johnson 100hp outboard

I don't have the boat yet. I just went and looked at it. Hopefully this weekend I can get it home.

Re: 1972 Johnson 100hp outboard

It is in fact a 72 100hp and hydro electric.

I got the boat home today. 1972 Pacer 150 18'. Got the title for the boat and the motor. Boat is junk though and will go to the landfill after I pull the motor. They said for $36 they will take it.

The prop spins clockwise as if in neutral, but meets resistance counter clockwise. I can turn the flywheel over back and forth and the prop turns both ways. Is this a good sign? Does this motor spin counter clockwise when going forward?

Next step is to try to get it running! I'll pull the plugs, spray down each cylinder with some fogging oil and turn it over manually a few times. Clean or replace spark plugs. Put some fresh fuel in her and try to start her up!