1959 Johnson seahorse 10

[JBF 1962]

I'm thinking I'd like an old 14-16' cedar strip boat to play with around the yacht club n stuff and I've found a 59 Johnson 10hp, just like my grandfather had years ago at the cottage...seems in good order. Does anyone have any ideas as to if this type of motor can still be somewhat serviceable? (parts wise etc) or am I just being dumb? LOL Thanks for your input.
John

 

[QuackAddict84]

Re: 1959 Johnson seahorse 10

I have done a lot of work on motors from that era. IMO they are the most reliable motors out there. I had a 60 18 horse that I restored completely, including paint. I put hundreds of hours on it, and never had to rebuild the powerhead. If the compression on that motor is good, it's a great candidate. The parts are readily available from any OMC dealer. Assuming it has good compression, a new water pump, points and plugs, carb rebuild, thermostat, and spark plugs will make it run like a new motor if you take the time to tune it well. They'll run WOT all day, and idle like a sewing machine all day as well. The only problem I have routinely is getting the gearcase completely sealed sometimes you just have to live with changing lower unit lube a few times a year. Good luck with it. Let me know if you have any more questions.

 

[Chinewalker]

Re: 1959 Johnson seahorse 10

Very nice motors to run - no problems finding most basic maintenance items (fuel, cooling, ignition systems). One weakness is the lower units can't handle as much abuse as some of the earlier models. If maintained correctly they're fine, but if they've been run with water in them, oil unchanged, etc., they can have their issues. Same goes for any older motor - the 10s with that style unit just take less abuse than others...

I've got a '58 Evinrude - very similar to yours - and it has been by daily runner for the last two summers. Starts easily, good power, and pretty quiet, too.

 

[kbait]

Re: 1959 Johnson seahorse 10

If that model doesn't have a fuel pump, you need the 2-line hose/coupler and pressure tank, or fit a fuel pump to it (lots of info if you search this forum). Ignition, carb, seals, rewind springs, waterpump kits.. all readily available. If it has good compression, I wouldn't hesitate to dig in.. They're nice runners!

 

[kfa4303]

Re: 1959 Johnson seahorse 10

Ditto. I agree with all posts here. Great little motors (I have '61 QD-22), parts are readily available and they're fun and easy to work on. You probably do want to convert it to a fuel pump and modern Johnson fuel tank, rather than the old 2-hose "siamese", pressure tank set up, but otherwise they're good to go.

 

[1946Zephyr]

Re: 1959 Johnson seahorse 10

I like the '57 model myself. It has the bigger 5 bolt lower end, which I found holds up better than the smaller lower unit, used from '58 on. These are great motors though and are easy to work on. Run that baby on 24:1 mix and she'll run forever.

 

[learningasIgo]

Re: 1959 Johnson seahorse 10

I agree with everything on here except the fuel pump. Those tanks aren't that hard to come by (look on craigslist and ebay) and they are easy enough to rebuild. Call me crazy, but I like to keep things as original as possible and I kind of like those old tanks anyway....but I am a little weird like that. If it's a '50s Johnson, I just love 'em. From the way they look to the way they run....they're just tough to beat.

 

[jay_merrill]

Re: 1959 Johnson seahorse 10

I have waaaaaaaaaaaay too much stuff in my workshop,so I'm cleaning it out and selling off some stuff. I just pulled my '58 Erude Bigtwins out to clean them up and get them running.

The first thing I did, was to start a compression check on both. I've done the first one and it has 119 psi on the lower cylinder and 123 psi on the upper. Based on the compression that I can feel on the other motor just by pulling the rope start, I expect it to be about the same.

If taken care of, the old OMC motors are pretty hard to kill. Take a look at the one you are considering and make sure there are no major mechanical issues. If not, yopu should be fine. You may have to replace the water pump impeller, redo the ignition, rebuild the carb, etc., but all that stuff is easy and you should be able to get parts.



???

 

[1946Zephyr]

Re: 1959 Johnson seahorse 10

I have waaaaaaaaaaaay too much stuff in my workshop,so I'm cleaning it out and selling off some stuff. I just pulled my '58 Erude Bigtwins out to clean them up and get them running.

The first thing I did, was to start a compression check on both. I've done the first one and it has 119 psi on the lower cylinder and 123 psi on the upper. Based on the compression that I can feel on the other motor just by pulling the rope start, I expect it to be about the same.

If taken care of, the old OMC motors are pretty hard to kill. Take a look at the one you are considering and make sure there are no major mechanical issues. If not, yopu should be fine. You may have to replace the water pump impeller, redo the ignition, rebuild the carb, etc., but all that stuff is easy and you should be able to get parts.



???

I bet if you give those oldies a little bit of run time, the compression will improve too.

 

[learningasIgo]

Re: 1959 Johnson seahorse 10

I like the '57 model myself. It has the bigger 5 bolt lower end, which I found holds up better than the smaller lower unit, used from '58 on. These are great motors though and are easy to work on. Run that baby on 24:1 mix and she'll run forever.

Just curious, but mine seem to have way too much oil at 24:1. I find that "it seems" better at like 32 or 36:1. What's your thought??

 

[kbait]

Re: 1959 Johnson seahorse 10

I run 'em at 32/1 and have never had an issue. Most folks go with the 24/1 recommended by OMC (now BRP). 24/1 to be safe.

 

[JBF 1962]

Re: 1959 Johnson seahorse 10

Thanks for all the input. I think i'll pursue this project, I've always kinda wanted one and the look/sound awesome. My one worry was that i'm on a weedy lake and i saw it take it's toll on my bro's early 70's merc 7 1/2hp burned out the coils and i think he was quoted 6 or 8 hundred for the parts. This has been in the back of my mind

 

[jay_merrill]

Re: 1959 Johnson seahorse 10

The semi-synthetic and full synthetic oils that are available today, are far superior to the natural oils of the 50s. Simply put, they do a much better job of keeping metal parts from touching one another.

The problem with your motor, is that there doesn't seem to be much of a knowledge base on cutting the mix, when a motor doesn't have needle bearings. Conventional wisdom here, which is worth listening to because there is a great deal of experience among the members, is that the motors like yours should be run at 24:1, no matter what kind of oil you are using.

I am a little more bold in this issue than some and might run an old 5.5, 7.5 or 10hp OMC at 32:1. The problem, however, is that I have never done this and cant speak with experience on the result. I have a lot of faith in synthetic oils, because I sold Amsoil back in the day, a read a lot of info on viscosity, shear, etc., but real world always trumps trying to guess what something is going to do in one application or another.




???

 

[kfa4303]

Re: 1959 Johnson seahorse 10

That must be a lot of weeds! Well even if that should some how happen, coils for these old OMC are only about $20 a piece and can be changed in about 30 min. with a few simple tools, if need be. There's also a lot of overlap with OMC parts, so if you have/get another one of similar size, you can often scavenge parts in a pinch.

 

[jay_merrill]

Re: 1959 Johnson seahorse 10

Just as a follow up concerning the reliability of the old OMC motors, I just did the second compression check (about 110 psi each cylinder) and ran both motors. I hooked a battery up to them one at a time and cranked them. Both motors started up and ran in less than one minute each.

Considering that they have not been run in five years and I didn't do a thing to either one of them, beyond squirting some light oil in the cylinders and turning the motors over for a few revolutions, before attempting to start them, I think that's pretty impressive. I didn't reset the point gaps, rebuild the carbs or anything else - just put them on some muffs, connected a small, portable fuel tank and fired them up!

I know that the new Etecs are very cool engines, but I swear by the old OMCs for reliability and overall economic value. Yup, the burn way more gas than the new ones, but I can buy a heck of a lot of gas with the thousands of dollars that I save in purchase/service cost.



???

 

[1946Zephyr]

Re: 1959 Johnson seahorse 10

Just curious, but mine seem to have way too much oil at 24:1. I find that "it seems" better at like 32 or 36:1. What's your thought??

Well, you can get away with it, because all OMC's 10hp and up are fully jewelled, with the exception of the wrist pins. So, 10hp and above can actually get by fine with 32:1. Just don't let it run hot. the '58 and earlier is less likely to run hot, since there is no thermostat. In 1964 and later, they called out 50:1 but truthfully, the only things that may have been changed is the alloy in the pistons. I do believe they had needle bearings in the wrist pins in the later models, but I honestly think that all fully jewelled powerheads are better off without needle bearings. This is because many motors have had the needles come out and get loose in the crank case and hashed up the whole inside of the engine. They are a unneeded waste of time and these engine are so much better without them. The rod on the wrist pin only has a maximum of a 20 degree swing anyway. Just no need. It's great to have needles in the crank and rod journals though.

The smaller motors are a babbot type rod and crank set up, so you definately want to stay with the recemendations. One mistake I commonly see, is the lightwins commonly are run too light on the oil mix, because the factory says it. The Lightwins are all babbot in the 3hp and 4hps, clear up into the 70's. All lightwins up to 1964 should be run at 16:1 and 24:1 for 64 and later. The 4hp was redesigned with needle bearings when they got a full shift set up.

 

[1946Zephyr]

Re: 1959 Johnson seahorse 10

Just as a follow up concerning the reliability of the old OMC motors, I just did the second compression check (about 110 psi each cylinder) and ran both motors. I hooked a battery up to them one at a time and cranked them. Both motors started up and ran in less than one minute each.

Considering that they have not been run in five years and I didn't do a thing to either one of them, beyond squirting some light oil in the cylinders and turning the motors over for a few revolutions, before attempting to start them, I think that's pretty impressive. I didn't reset the point gaps, rebuild the carbs or anything else - just put them on some muffs, connected a small, portable fuel tank and fired them up!

I know that the new Etecs are very cool engines, but I swear by the old OMCs for reliability and overall economic value. Yup, the burn way more gas than the new ones, but I can buy a heck of a lot of gas with the thousands of dollars that I save in purchase/service cost.



???

Yes, old OMC's are the best. No one will ever beat their reliability and quality.

 

[JBF 1962]

Re: 1959 Johnson seahorse 10

so, what everyone says about them must be true, unlike the old mercs, fast and impressive in thier day, but hard to source parts as they tended to be re-designed often