Would you buy it?

[auldscott]

I may have a chance to buy a mid-80s Johnson 35 hp. The ad says it has low compression in one cylinder.

Did this era of OMC 32 cid motors have a history of problems? I know the early 32 cid motors had a reputation for overheating, but understand that the early and mid 80s were good runners.

Low compression is worrisome, not for the problem itself but for the other problems that might have come from the cause of the low compression: overheating, too little oil, etc.

Would you buy such a motor without being able to run it? How much would you risk should it be a junker?

Thanks.

auldscott

[amuller]

You haven’t given us enough information to offer a meaningful opinion. Absent info to the contrary I’d assume the powerhead needs to be dismantled, bored and honed, new pistons and rings…. Do you have the skills, time, and motivation to do that yourself? Unless you do, the cash value of such a motor is likely very low.

[retiredoz]

Probably yet another 100:1 casualty ? I would be leery of making a large investment unless I knew where another good powerhead is to be found…

[billw]

If/when they overheated, they would tend to loose a head gasket. People would sometimes fix the pump but not the head gasket; and continue to use the motor, even if it ran poorly. This would lead to an etching/eroding of the head and block gasket sealing areas, making the power head useless. It didn’t take very long for it to happen, either. Salt water motors were, of course, worse. I am not saying for sure that this will be your problem, but it did happen.

Long live American manufacturing!

[outbdnut2]

They are known for not running smooth at speeds above idle until you advance to a much higher speed. It seems it takes a lot of throttle advance to get over the rough running range where it is switching over from the low to hi speed carb passages. The rough running at these speeds sounds very irritating when you want to go slow on a pontoon boat, or any boat!

If it has electric start, there is no choke, instead has an electric pump that pulses gas into the carb throat. You have to keep pushing in and out on the key for a while after it starts to keep it running when cold – another nuisance. and yeah – the 100 to 1 thing didn’t work out – use 50 to 1.

If it still has the automatic oil-mixing fuel tank – either toss it or open it up and disable the mixing. Most of these tanks gave trouble and were tossed or that function defeated within the first year or two. The low oil sensor would randomly shut off the gas with the oil tank nearly full.

I’ve had one and would not buy another.
Dave

[fleetwin]

Well, like everyone says, you have to make the assumption that the powerhead is toast, and make an offer based on that assumption…
Have you seen the engine? Is it fresh or salt water? Is it in nice cosmetic/mechanical condition otherwise? Gearcase look OK, not busted/cracked/leaking?
There are so many factors that will influence your offer, how much does the seller want for it?
If you buy it, you can hope that the head gasket is just blown, and perhaps the powerhead can be resurrected. If not, just keep looking for a reasonably priced used powerhead, they are out there….Just be sure you are not buying more junk though…

[chinewalker]

I’ve lucked out on a few of these that had minimal cylinder wall damage. Honing, a used piston and new rings got them going again. I’ve also rebuilt a few whole hog with new pistons, boring, etc.

[rook49]

quote auldscott:

Would you buy it?

Nope, not I.

If I want a headache I’ll just get my wife to hit me in the head with one of her cast iron skillets instead of paying for it. It’s a lot cheaper and at least someone will get some pleasure out of it. 🙂

[auldscott]

Thanks to all for the thoughtful replies. I’m not adequately skilled to take on a rebuild and would have to tap into the expertise of friends, or perhaps ask one of them to do the work if it turned out to be extensive. That is a lot to ask of a friend. Guess I will pass. Would like to get my hands on such a motor, though.

[frankr]

We seem to be assuming it was an early one (overheating) and/or Accumix or 100:1 etc. But I don’t see anywhere that any of that is true, except maybe, based on low compression. After they got the overheating problem fixed and voided the 100:1 thing, I would say they are fine motors. At least I consider mine (1984) to be that way.

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