Home › Forum › Ask A Member › Johnson SD 10 15
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Sam M..
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October 6, 2025 at 9:27 pm #300413
Does anyone have any experience with an SD Johnson 16 hp?
My autistic 21yo son is finally showing interest in wrenching on outboards. He bought a Peter Hunn book and has shown an affection for 1940 ish outboards. Actually he’s fascinated with knuckle busters too. He found a PO 15. 22 hp on Marketplace. That one may be a tad large for the 14 foot.
Any suggestions?
October 6, 2025 at 9:50 pm #300415I don’t know anything about that johnson, but you are probably right about a po-15 being too big. Unless the transom on the boat you speak of is really beefed up, it would probably be unsafe to run such a heavy motor on such a small boat. While my collection dosen’t hold a candle to many of the members here, I’ve really enjoyed and mostly stuck to the 1-4 HP motors from the 20s 30s and 40s. It’s nice to be able to move them around easily, especially if one is just starting with outboards.
"Outboards seem to multiply exponentially..........I find that for every finished project, there are two more waiting to be completed."
October 7, 2025 at 7:37 am #300420Adding to the story:
We own a number of 50’s and 60’s outboards. 5-18 hp.
We have a 55 Evinrude Triumph on our 16 foot.
I’m looking for something he can take ownership of. Being autistic he struggles with some things. Telling time, and math. Personal relationships are a huge struggle too.
He goes to an adult special needs school, where they teach basic life skills. He joined the robotics team and I became a coach for his team. This is where he showed an interest in mechanics. God Bless his teacher for spending quality time with these kids.
We have a 14 foot Sea Nymph 14R that we take out on Lake St. Clair. He likes to go fast (who doesn’t). This is why I prefer a 12hp to 20hp. We can work on it and fish with it. He loves fishing.
I’m really happy he’s finally showing an interest in working on something. Not just watching me from a distance. I want him to own this. To fix it, to struggle a bit and overcome. Nothing feels better than breathing life back into an old piece of machinery.
Thanks to everyone here.
God Bless
Don
October 7, 2025 at 11:07 am #300426Every thing disappeared so I’ll try a it again in 2 parts- I searched SD Johnson 16 hp and found a few You Tube videos. New to me. Interesting motor. I have 2 suggestions as to motors you might consider. First is the 1949-50 Mercury KF-7 Lighting. This Super 10 is actually closer to 15 hp. They are plentiful and not expensive. They can be some what of a challenge to work on as you have to devise substitutes for the special tools that were made for these motors but we have solutions for many of them. If you have the old impeller there is a member who can make you a replacement using the center from the old one. Used parts are obtainable, as well as some new, like gaskets, from several dealers. While these motor had 120 lbs or more compression when new, most have been well used. However the compression is 90 lbs. in this example I just uploaded a video of yesterday. After the repair part it shows the motor running. https://youtu.be/3aEQ773QzuM
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
October 7, 2025 at 11:11 am #300427The second motor I would suggest is the 1928 or 1929 Elto Speedster. Even though you spin the flywheel (in the opposite direction you want it to run) to start them, these aren’t considered a “Row Boat” motor by some as they are not brass. Although rated at 7hp. its closer to 11 or 12. They have a very interesting ignition that will need some repair, and the coil will need to be rebuilt as the wires will be rotten if you find an example that has been resting for decades. The gas tank is the biggest issue with these because of the vibration. Look for cracks around the mounts. They will all have dents. If they will let you, pour in some alcohol and check for leaks. I’d show you how to get the alcohol back out but too many links here and everything disappears. They don’t use an impeller but there are no seals in the gear case so it needs some regular attention if your running them a lot. Your son may not want this much of a challenge but all the issues were over come. https://youtu.be/lJ6cXeWWi7g
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
October 7, 2025 at 1:38 pm #300429KF-7 sounds like a great choice. He wants a Merc too. They look great too.
October 7, 2025 at 5:13 pm #300438I agree with tubs. While I’ve had issues with the one ke-7 I’ve owned and posted issues about, they are cool motors. I’m looking to buy an ELTO speedster myself.
"Outboards seem to multiply exponentially..........I find that for every finished project, there are two more waiting to be completed."
October 8, 2025 at 8:00 am #300425I searched SD Johnson 16 hp and found a few You Tube videos. New to me. Interesting motor. I have 2 suggestions as to motors you might consider. First is the 1949-50 Mercury KF-7 Lighting. This Super 10 is actually closer to 15 hp. They are plentiful and not expensive. They can be some what of a challenge to work on as you have to devise substitutes for the special tools that were made for these motors but we have solutions for many of them. If you have the old impeller there is a member who can make you a replacement using the center from the old one. Used parts are obtainable, as well as some new, like gaskets, from several dealers. While these motor had 120 lbs or more compression when new, most have been well used. However the compression is 90 lbs. in this example I just uploaded a video of yesterday. After the repair part it shows the motor running. https://youtu.be/3aEQ773QzuM The second motor I would suggest is the 1928 or 1929 Elto Speedster. Even though you spin the flywheel (in the opposite direction you want it to run) to start them, these aren’t considered a “Row Boat” motor by some as they are not brass. Although rated at 7hp. its closer to 11 or 12. They have a very interesting ignition that will need some repair, and the coil will need to be rebuilt as the wires will be rotten if you find an example that has been resting for decades. The gas tank is the biggest issue with these because of the vibration. Look for cracks around the mounts. If they will let you, pour in some alcohol and check for leaks. I’d show you how to get the alcohol back out but too many links and everything here can disappear. They will all have dents. They don’t use an impeller but there are no seals in the gear case so it need some regular attention if your running them a lot. Your son may not want this much of a challenge but all the issues were over come. https://youtu.be/lJ6cXeWWi7g
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
October 8, 2025 at 1:43 pm #300454What difference is there in the KE-7 and the KF-7,?
October 8, 2025 at 2:49 pm #300456Ok according to the internet. the KG is more advanced. Better reed system and better carb. Also more hp. 14 VS 18 HP
Above post was meant to differentiate
Between F and G motors.
I’m finding plenty of KF but no KG on marketplace.
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