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15 hp johnson / evinrude

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ht43

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I'm going to be buying a johnson or evinrude 15 hp outboard motor either 80s or 90s probably. Is there any years I should stay away from?
 
if ur going to buy something that old investigate if a piston rebuilt has be done, if not anticipate of doing it. those engines run hot due to vro causing oil starvation resulting is worn out seals rings & cylinders to get out of specs.
 
fishhawk90 said:
if ur going to buy something that old investigate if a piston rebuilt has be done, if not anticipate of doing it. those engines run hot due to vro causing oil starvation resulting is worn out seals rings & cylinders to get out of specs.
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Somebody still does know how VRO works.
 
Exhaust relief holes would plug.----Motor would not idle properly .-----You would end up pulling your hair out with carburetor cleaning / points cleaning / sparkplugs etc , etc .----Just because those wee holes in the tuner were plugged !!
 
I have 2 of them -1976 9.9 Evinrudes. Maybe that's my problem with the one. How can they be cleaned and where are they at? I have cleaned the carb and checked points, new plugs, compression is 118 and 120 by my gauge. Runs fine for a minute or so in the barrel then backfires a bit and I can rev it a bit and it will be good for a bit then starts over. The other motor done the same and got it all dialed in and runs great-just this one is a bit frustrating. Sorry to hijack this thread but I guess if the original poster wants to learn I have a problem with one!
 
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ht43 said:
I'm going to be buying a johnson or evinrude 15 hp outboard motor either 80s or 90s probably. Is there any years I should stay away from?
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A 15HP from the 80's or 90's will be just fine. It will be a pre-mix only engine, but that's fine. These are very reliable little motors with just a little bit of maintenance. I have a '79 9.9, which is nearly identical to a 15HP, and it runs like a top. I had to chase some cooling issues, but once that was solved it has been rock solid reliable.
 
So what causes those exhaust relief holes to plug? I may have the answer, but for now I am listening. Have had lots of those very first 9.9 and 15's. The only basic difference that means anything is the carb.
 
timguy said:
So what causes those exhaust relief holes to plug? I may have the answer, but for now I am listening. Have had lots of those very first 9.9 and 15's. The only basic difference that means anything is the carb.
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The main problem with them is the ignition system did not have a strong spark. Thats why a little hotter NGK plugs work well in them. There was also problems with the carbs not being very good. And the magneto rings were poorly machined. Because of the weak spark and bad carb you got carbon build up. Not to mention gearcase issues with leaking.
 
Always been a big fan of these motors, and have owned a dozen of them (still own a 1989). As said before, DEFINITELY stay away from points, or magneto ignition, that was made until 1976.
These motors are much more unreliable and rougher running than the post 76 CDI.
Personally I prefer the post 87 models because they have the thermostat on top of the cylinder head, as opposed to the bottom of it which makes inspection/replacement a real PIA as it requires latch removal, and can take you a couple of hours as opposed to 5 minutes with the top placed one.
These motors are virtually indestructible with the proper maintenance and have one of the best power to weight ratio ever in the 15hp and under category.
The only thing you must do before buying one, is measuring compression. I would leave anything under 95 (preferably 100) in compression alone, unless you're planning on rebuilding the power head, which in my opinion is not worth the time spent on it and money on parts, since you can find pretty healthy ones under $500.
As timguy said, the only difference between the 9.9 and the 15 is the carb throat which allows the motor to pick up a few hundred more RPM and increase in hp, although from my experience with both 9.9 & 15, the power and top speed difference between both can be hardly noticeable.
One last detail that can be of importance if you plan on using a tiller arm extension: The kill switch is located at the end of the tiller arm until sometimes in 1991 when they moved it in the middle of it, which allows access even when you have an extension clamped onto the handle.
Good luck!
 
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I must have one of the rare good ones as it runs great especially considering its almost 43 years old. It has been taken care of though and the other one I hope to get running as good.
 
I like the 84 models with the simple throttle handle.------Not a fan of the handles on later ones with the cable operated throttle.-----Full of expensive little bits.
 
I like the mid 80's. Still have several 73 to 76 models. But they have been run on Amsoil for the last 30 plus years. Still waiting for one to melt down on me, but it hasn't happened yet. Often run 2 15's together on 18 foot Alumarine's, made in Winipeg Canada. When freighting, I will run a 25, flanked by 2 15's.....talk about power.
 
Took a bit but I think I have it figured out. Exhaust relief is the exhaust under the bottom engine cover! Dont see how that could get plugged but I suppose if the motor does nothing but troll it could be. I dont mind the old point system as its a lot cheaper to replace than the electronic ignition. Never had gearcase leaking either. Did have to replace the prop seals once because of fishing line.
 
I mentioned that the holes that plug are on the exhaust tuner.---Perhaps you missed that simple fact.-----Perhaps you do not know what the tuner ( aka inner exhaust housing ) is, I do not know your experience.
 
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Viewpoint from a guy that worked in the dealers shop during those years ('7-'76), I can say those were terrible motors. We could not keep them running, and neither could the factory. They sent several kits to "fix" them, none of which worked.

OK, so there are some still out there that are still running. Those are the ones that didn't get junked early on.
 
Didnt know what the exhaust tuner was. Only experience is trying to keep old motors going with a lot of thanks to guys like you so a I can.
 
Agreed-----Know of a dealer that said to his shop helpers.-----" It ran ok when we took it out of the box . So I want this motor taken apart to see what is going on "----We have to figure it out because factory is of no help to us.
 
Yes, I have made mods on my early 70 15's. The knowledge and ability to make those mods back then was not yet conceived. I started at a Johnson/Evinrude dealer in 1972 it was my first "real" job. I remember well, the problems, brothers. Fell in love with outboards at an early age.
 
nytebyte... Your post #8 indicates a engine running only to burn the fuel in the engine's carburetor and possibly the powerhead's associated fuel line... then running out of gas.

If the engine continues to run if you constantly pump the fuel primer bulb (acting as a manual fuel pump)... replace the fuel pump.
 
Thanks Joe. It will be awhile before I have a chance to run it, snow decided to come with colder weather. I will give that a try. This one has been setting for a long time-maybe because it never would run right for the original owner.
 
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