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Newbe buys 1958 Johnson 7.5 hp outboard

T

Tapsnap

Member
Hi everyone, I’m new to this forum and new to outboard engines. I usually hang out on the wooden boat forum, where I have previously built two other boats. A row boat and a sail boat. I am currently beginning my next boat which is a flat bottomed skiff. I was driving past a yard sale this past weekend when I spotted a boat engine. After about 10 minutes I found myself driving back home with my first ever boat engine. I knew nothing about it or what condition it is in, only that it does not currently work. After doing some research, it turns out it is a 1958 Johnson 7 ½ hp AD-12. After taking off the hood I discovered some obvious problems. Firstly, the starter cord is stuck out and won’t retract and secondly the spark plug connector has been torn off. But other than that the whole engine looks like it is in pretty good shape for its age. I took a quick look inside the starter assembly and discovered that the retracting spring is broken. So that solves that mystery, but I thought I would ask all of you experienced with these outboards what your recommendations would be to getting this motor back up and running again. I noticed there are carburetor kits and gasket kits for this engine. I guess the whole thing should be refurbished before I try to start it. I’ve never worked on one of these things before, but it seems like something I could learn by just taking the thing apart and asking a lot of questions on this forum. The manual would help too. Anyway, I have time because I have only just finished lofting the boat design and am in the process of making the station molds on the new boat. Can someone give me an idea of how much it might cost to refurbish this old motor just in parts? I paid $125 for the motor and would like to keep it under $500 all in.

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Looks pretty decent.....we can walk you through it. Several advisors here on the forum grew up fixing these little gems. Get a 2 line pressure tank with it.....WITH COUPLING? HOPE SO! First thing is turn it over with a little mixed gas squirted into carb. You can test compression, plugs out, with your cordless.....or any variable speed drill. Get us some compression numbers and then we will know if you got a motor or not.
 
Ha! Good point, Swarlos. Could also wrap a rope of course, eh? Pull it for all your worth. Should build full compression by 5th pull.
 
Thanks everyone. I don’t have a fuel tank yet. I noticed that a lot of people install a fuel pump on these engines to avoid some inherent problems with these two line pressure tanks. Is that something that you would recommend?
 
There is nothing wrong with a pressure tank in good condition !-----Better quality then some of the modern plastic junk, in my opinion.
 
Amen, Racer. The pressure tank is brilliant engineering. Why? .....closed system, no fumes at tank.....large opening in case you ever have to clean inside.....gaskets available for 7 bucks....raised cap with threads.....thicker metal in tank construction.....no fuel pumps to fail that run on vacuum......nice carrying handle.....more reasonable hooks for coiling fuel line.....heavier galvanize throughout tank......smaller diameter, more flexible hose......hose made of high quality latex rubber......fitting/coupling made of aluminum, not plastic.....o-rings that are reliable and easy to replace.....4 gallon tank perfect dimensions for a smaller boat, not a low and broad tank that takes the large space as a single line 4 gallon.....nice strong bottom lip on tank to hold up off floor of boat, not wearing away like a plastic tank..... completely resistant to UV.......paintable......weldable......nice large, fine pickup screen.......extremely reliable primer pump, no worthless synthetic rubber, expensive squeeze bulbs to leak and get hard in the cold and crack.......the list is almost endless.......
Sorry but I'm old fashioned.......but this is REAL INTELLIGENT ENGINEERING!
 
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Okay, sounds like you are pretty firm on your opinion about that. So is the best place to look for the 2 line tanks on ebay or is the a better source?
 
E bay or maybe Tim's Outboard in Hackensack. If you get really stuck for one and you find out that Fleetwin motor is good, then you might be able to talk me out of one. You have to get on that compression test before you make any calls, my friend.
 
You might be shocked to learn that those No-Longer-Available dual line fuel hose connectors' last price was $149.97 here at marineengine. Just sayin' so you will recognize a bargain when you find one.
 
Change it to a fuel pump if it was such great engineering it would still be used. The same people who tell you how wonderfully engineered the system is will tell you the same thing about the fuel pumps. For a $150 you can buy a nice metal tank and all the pieces you need to convert it.
 
Those connectors are around, I have never, ever had to pay more than $20 bucks for one. Once at a motor sports repair auction (Lyle died of lung cancer) I bought 10 pressure tanks......some with hose and fittings.....with the boat trailer they were piled on....along with 15 regular steel suction tanks.....and 10 plastic tanks.....all for $35 bucks, and towed the trailer home besides. Deals like this can be found. If you have a good motor and can find a fitting, even without a tank.....I will sell you a tank for cheap. The single line tanks eventually develope leaks at the check valve pin, as well as having a tiny filter screen. Still they are way better than plastic. Almost every used plastic tank I get in here with a repair job.....has a problem....mostly a leak on top somewhere, letting in water, and or a worthless pickup tube and filter. It's your call, but I like em, run em, trust em, and live by em.
 

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They used the pressure tanks for about 6 yrs. Scott Atwater never used them I do not believe Elgin did either and Mercury only used them for 1 or 2 yrs kind of like the Edsel or the 4/6/8 Cadillac. I don't know why they keep bringing up plastic tanks, There are many more standard metal tanks than there are pressure tanks. So the parts to convert are readily available and very easy to find well worth it in my book. The people who tell you those hoses last longer than any other rubber hoses, well thats just shine. Even OMC thought the fuel pump was better.
 
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Your a bit off on years of use for pressure tanks but agreed on everything else. I had an 8/6/4. Cubic inch was about 380?.. down from my 1977 with the 425 TPI. I'm a Caddy guy. Still drive my 95 Fleetwood with fuel injected Corvette 350. The 77 Fleetwood is sunk in the ground under a balsam tree.
 
It is a cheaper to go with a fuel pump instead a pressure tank. You can pick up a universal fuel pump like this one I purchased for my 5.5 hp '57 Evinrude that I paid $10.11 with free shipping from Walmart's website. You can also find them on ebay for about the same price.

I like these little pumps because they're aluminum instead of plastic and they have mounting holes that you can attach to some metal strap material with bolts instead of strapping them on with wire ties like some people are using on the youtube videos.

There are some pretty good videos on you tube showing how to make the conversion. It does require removing the intake manifold and removing the check valve and plugging one of the holes with a rubber vacuum cap but it's pretty simple.


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Then I found a very clean regular single line tank on ebay for $60 bucks.

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I’ll be driving past the place that had the yard sale on the weekend where I got this engine. I’m going to stop by and see if they have the tank that went with the engine. Maybe I’ll get lucky.
 
Good. Might still have it with fitting up in the back of the shed at the lake.
That conversion that Rook did is always your second choice.
 
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I restored an AD-10 (the 1956 model) recently. Do yourself a favor and replace the ignition coils and get the ignition tune up kit. Just make sure to have the coils far enough in, otherwise the inside of the flywheel will catch it.
You can also hook a fuel line up directly to the carburetor and keep a fuel tank on a ladder and let gravity be your fuel pump while you work on it and until you get the tank and hose fittings.
These are fun little motors and easy to work on, the only thing I don't like is removing the power head to change the impeller, but it's not that hard, just the two front screws are tough to get back in.
I would also recommend to go down to the hardware store and get new Philips head screws when you do remove the power head, it will make putting it back on easier.
 
Good advice.....these really are sweet motors. Get stainless steel bolts or "cap screws".
 
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Redrobinyum3 said:
Just make sure to have the coils far enough in, otherwise the inside of the flywheel will catch it.
Click to expand...

If you work on them very often you can buy a useful coil locating ring tool that makes it easy to set the coils. I got mine from Richard's Outboard Tools on the Internet for $25 bucks. You can do it just fine without the tool but it just makes life a little easier or at least it does for me.
https://richardsoutboardtools.com/

I meant to add. If anyone finds that it's hard to adjust the new coils up to where they're supposed to be like there's not enough adjustment to where it feels like the slotted holes need to be reamed out for more adjustment. Well after going around and around trying to figure this out I've found the problem to be with the size of the rubber boot that's on new coil wires these days. Those boots where the wire enters the coil are bigger than they used to be and it makes it hard to push and adjust the coil to where it's supposed to be. At least it has on the coils I've purchased in the past couple of years. I've taken old boots and replaced the new ones on some and others that were close I just pushed as hard as I could with one hand while tightening down the screws that hold the coil in place. Hope this helps some poor unsuspecting soul. It had me baffled for a while.


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Often the stator bushing gets a little loose and you have to manually compensate for that. I test my calculations with a piece of Scotch tape over the coils or the magnet, then lightly tighten down the flywheel and turn it to see if it rubs under different stator positions, and with magnetic attraction in the mix.
You know I'm with you on the pressure tanks, Racer. Extremely effective way to provide reliable and clean fuel.
 
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Woah! I'm gonna sh!+can all my pressure tanks ....... if I didn't know better, eh? I would like to have a nice friendly talk with the writer of that second article for sure. In well over 50 years of operating....with my Dad....2 remote camps in NW Ontario.....I have yet to hear of a 1949 to 1959 pressure tank exploding or causing a fire. To me.....even more bothersome, is the possibility of a higher pressure fuel pump, blowing a line and spraying gasoline and fumes on a hot powerhead, trapped under a cowling with an immediate source of ignition......so what's safer? You tell me!
 
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timguy said:
Woah! I'm gonna sh!+can all my pressure tanks ....... if I didn't know better, eh? I would like to have a nice friendly talk with the writer of that second article for sure. In well over 50 years of operating....with my Dad....2 remote camps in NW Ontario.....I have yet to hear of a 1949 to 1959 pressure tank exploding or causing a fire. To me.....even more bothersome, is the possibility of a higher pressure fuel pump, blowing a line and spraying gasoline and fumes on a hot powerhead, trapped under a cowling with an immediate source of ignition......so what's safer? You tell me!
Click to expand...
It is absolutely the pressure tank that is safer!!! Because when the fuel line breaks between the carb and the fitting, all the fuel the tank was pushing out goes to magic fairyland. And all the pressure that was in the tank goes to pressure heaven and runs with puppies. Or when you get a pinhole in the fuel line and it sprays gas all over you, well thats just fuel to light your cigar. When a fuel line with a fuel pump breaks or gets a pinhole in it, well thats under vacuum so no gas on your legs. That is a terrible thing no fuel to light your cigar. If a motor with a fuel pump starts on fire and stops running it will stop pumping fuel. And that is not good no time to roast marshmellow. Now when a pressure tank motor starts on fire that is good thing. Since the tank holds pressure it will continue to spray gas on the fire, plenty of time to make s'mores.
 
Well, it was worth a shot. Went to the place where I bought the engine and was told that they got rid of it years ago when they saw that the hoses were perished. So, I’ll be looking for one elsewhere. I don’t have the money right now to shell out another hundred bucks, so it will be a while before I get back to this. As I said, it’s not something that I need to work on right away.
 
After what was just posted by Mr. Scott .......I guess I should start selling them, eh? Great post.....gonna screen shot and save it. Maybe I should start smoking.
 
The pressure tanks are the most dangerous to have because aliens use them to power their flying saucers and if you're cruising along on the lake minding your own business with your old '57 Evinrude and they suddenly spot you they'll dive down and take it. I can't count the times it happened to me and I've also gotten burned by the fumes from their old leaky pressure tanks on a number of occasions. I didn't want to say it but that's the reason I switched over to a fuel pump. Don't say you ain't been warned.
 
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