Would like to bring Seahorse back to life

[TennesseeJim]

I am just getting back into fishing/boating after a 7-8 yr. layoff while my son played year-round baseball. That's come to a close (he's 19 now) and he has approached me about getting back onto the water with him. That's all I needed to hear!
Right now our 14 ft. 60s era Sears aluminum is pushed by a Mercury 110 9.8 hp. A little slow but reliable. My uncle gave me his old Johnson Seahorse 18 (FD-12) years ago and it used to get us around at a pretty good clip. The last time we had it on the water, we were heading back to the truck at full throttle when something snapped, the motor reved, and we immediately stopped. A guy in a big cruiser was nice enough to tow us the last two miles back to the ramp. The Seahorse has now been sitting in my basement gathering spiderwebs for the last 8-10 yrs.
I'm pretty handy - I do all my own auto maintenance, so I'm considering opening her up to see what I can find. I guess my question is multi-pronged. Do you guys like these motors? If maintained, are they as reliable as can be expected? Are manuals and parts readily available? I'm a real fan of it's cool appearance and it's obviously very solidly built. It also has electric start, which is a big plus for me. Any comments are welcomed, thanks - Jim

 

[aganser]

Re: Would like to bring Seahorse back to life

Jim,

I'm going to suggest you post that question here:

http://www.aomci.org/cgi-bin/yabb2/YaBB.pl?board=askamember

These guys can help you out.

Bob

 

[tashasdaddy]

Re: Would like to bring Seahorse back to life

FD 12 is a 1958 18 hp. plenty of people here with experience, with them, no need to send them any where else.

first thing i would do, tilt the motor up, ( plugs up). remove plugs, and put some marvel mystery oil in each cylinder and leave for a day. this will lubricate the rings. now lower the motor allow oil to drain out, messy. now try to turn motor over, with plugs out, your hands, do not stand behind plug holes, may squirt water on you.

if it turns easily, pull the rope and get the excess oil out. now check compression and spark. the motor is going to need new fuel lines, alcohol resistant.

do you have the pressure tank that goes with the motor, if so, replace those hose also.

fuel mix is 24/ 1 for that motor.

carb 99% will need to be cleaned and rebuilt. many goods tips here. http://forums.iboats.com/showthread.php?t=299680
that's enough for now. lets us, know your results.

 

[shootindave]

Re: Would like to bring Seahorse back to life

If the motor suddenly reved and you stopped the shear/drive pin probly broke (sheared). Been there a few times.

Pull the cotter pin off the cone, unscrew the cone from the prop, pull the prop off. If the shear pin falls out in two pieces, there's the problem.

- Dave

 

[McGR]

Re: Would like to bring Seahorse back to life

Those old 18hp OMCs are great all around fishing motors. Most of the tune up and regular maintenance parts are still readily available. There are also plenty of new old stock and used parts available. Some parts may take a little searching, but they are out there. With a little maintenance you should have yourself what is still a very viable reliable motor.

 

[1946Zephyr]

Re: Would like to bring Seahorse back to life

The '57-'58 Johny/Rudes are probably the best motors ever built. I would bet that once it's properly tuned and cleaned up, it'll prove to be more reliable than your Merc 110. I've owned a few of those in the past and all have come back to life willingly. Whatever parts you can't find at your local dealorship, you should easily find at either Seaway Marine in Seattle Wa, Engine Blade and Prop, in Milwaukie WI, or the aomci.org website. There are still thousands of these motors out there running reliably. Good Luck, I hope this helps.

 

[tashasdaddy]

Re: Would like to bring Seahorse back to life

you can find all the tune up part here at iboats. http://www.iboats.com/Johnson_Outboard_Parts/dm/view_id.271265

 

[asdasc]

Re: Would like to bring Seahorse back to life

I love my Johnson 18hp from '59. It is very reliable and i use it every weekend. It will even run really well on one cylinder if you adjust the points wrong!

Go to the 'top secret info' and read the FAQ on awakening a sleeping outboard. My guess is that there is very little wrong with it, but you will want to rebuild the carb (easy) and replace the points, condensors, coils, plugs, lower unit lube, and impeller, just to give you the peace of mind that all is well when you go out on the water.

Other things to check for the symptoms you discribed are:
- Drive pin (already mentioned, behind the prop)
- shift adjustment at the time (since it is off the boat, this is no longer an issue)
- shift linkage - behind the oval cover on the starboard side of the motor about half way up. There is a connection in the shift linkage that will sometimes come loose. When this happens, you can only get down into reverse and you can't pull it up into drive
- spun prop - this is usually only a problem at full throttle. Inside the prop is a rubber coupler that connects the prop shaft to the prop blades. It is a friction fit, and you can't see it external to the prop. After many years it dries out and starts to slip under load. You need to get the prop re-hubbed at a local prop shop. I think it is about $25-50? I have never had it done.

Good luck, and keep us posted!

 

[TennesseeJim]

Re: Would like to bring Seahorse back to life

Thanks guys ... this is my first thread on the site and I'm feeling like I came to the right place - very encouraging! I will try to make an initial diagnosis - hope it's just a shear pin, that sounds logical, and post that back to you. I will also do the Marvel oil treatment and see if she's free. The rest may need to wait until closer to Spring as I am dealing with some of the same issues on the 9.8. I've ordered parts for it already. Our goal is to get something in working order fairly soon so we can get in some wintertime striper fishing like we did in the good old days.
Happy holidays to you all and I will be in touch.
Jim

 

[KB1]

Re: Would like to bring Seahorse back to life

Good eve and Merry Christmas to you and yours!!

Had the same motor up until last year when I decided to sell it and another motor as I was not using it anymore (size upgrade). Was the most reliable, smooth, trouble free of about a dozen John/rudes I've had. Anything I can help you with, I'll be more than happy to!! No spare parts around, but my cobwebs on it haven't started to take hold yet.

Happy Johnny'ing!!

P.S.
Not far from you. Jackson, TN.

 

[samo_ott]

Re: Would like to bring Seahorse back to life

I have many 50's J/E 18's. I love the engines. Run em all the time. I have the parts manual with diagrams for the Evinrude '58 18hp if you want it. It's virtually identical. Private Mail me your email address and I'll send it to you.

To me it sounds like the drive pin. Could be shifter linkage also.

 

[kbait]

Re: Would like to bring Seahorse back to life

I've had about 20 of em.. Always strong, and coax-able to manageably slow idle. I now use a '75 15hp, not as fast, but idles way slower for trolling and 1/3 less fuel for what I do. If I need more power, I put an 18 back on (with the 2-line tank). Merry Christmas!

 

[ChrisAG]

Re: Would like to bring Seahorse back to life

I now use a '75 15hp, not as fast, but idles way slower for trolling and 1/3 less fuel for what I do. If I need more power, I put an 18 back on (with the 2-line tank). Merry Christmas!

Last Fall I had a chance to compare the top speed of an Evinrude 18 (1958?) and 1978 Johnson 15 on the same boat. Both had been in long-term storage for about 25 years, and were overhauled before running (carb kit, plugs, gear oil on both motors, plus new coils on the 18). The boat was a 14' Starcraft Sealite rated for 15hp, very lightly loaded (just oars, a bailer, about two gallons of fuel, and myself).

The handheld GPS indicated 40 Km/h (24.8 mph) for the 18 (averaged two directions), and 38 Km/h (23.6 mph) for the 15. Each test was done within 20 minutes of the other. Very close results (1.2 mph), considering the 18 is about 22 cubic inches, and the 15's dispacement is 13.2 cu. in.

The big surprise was a 1990 Mercury 8, which managed a respectable 31 Km/h (19.3 mph).

 

[tashasdaddy]

Re: Would like to bring Seahorse back to life

the 1958 and 1978 motors hp, was rated at the power head. the 1990 was rated at the prop. that makes a big difference.

 

[BigB9000]

Re: Would like to bring Seahorse back to life

Last Fall I had a chance to compare the top speed of an Evinrude 18 (1958?) and 1978 Johnson 15 on the same boat.

was the same prop used in this test?

 

[ChrisAG]

Re: Would like to bring Seahorse back to life

No, they're completely different lower units & props. The 18 has a drive pin prop and exits its exhaust below the anti-cavitation plate, while the 15 has through the hub exhaust. The standard OEM propellers were used.

 

[kbait]

Re: Would like to bring Seahorse back to life

My boat is fairly heavy, and the 15 planes out w/two people, and the 18 planes out plus probably 4mph. If you had loaded the starcraft, you'd probably find the same (standard props on both)

 

[ChrisAG]

Re: Would like to bring Seahorse back to life

I would agree, the 18 would probably do better with a loaded boat, again the displacement factor coming into effect. An interesting test would be the 1981+ 15hp, which gained a tuned exhaust and a claimed torque boost over the earlier models (that might be when they started rating hp at the prop). Those models might have equalled the 18.

 

[ruckerra]

Re: Would like to bring Seahorse back to life

Don't be afraid. Dad gave me his old 47 Johnson TD 20. That thing will NOT quit! Simple to maintain doesn't look that great be she runs

 

[ruckerra]

Re: Would like to bring Seahorse back to life

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