Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

[Zapit2um]

I have a 1960 18hp Johnson seahorse (FD14) and am thinking about buying a 1959 18hp (FD12) because I need a new lower unit. Are they interchangeable?

 

[64osby]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

Pretty sure they interchange, both should have 4 bolt lowers. Just make sure.

 

[kfa4303]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

HI zapit. Based on the model numbers you posted, it looks like you actually have a '60(FD-14) and a '58(FD-12). As 64osby said, as long as they both have the same bolt patterns for the LU, they should just bolt right in place. Virtually all of the components on the power head are interchangeable as well. However, Johnsons started getting fuel pumps from the factory in '59, so the '60 model should have a fuel pump, whereas the '58 will use the vintage 2-line pressure system, but can be converted to a modern single line system if you want. Here are some handy links.

Maintaining Johnson E & FD Serie
Converting the Old OMC Dual Fuel

 

[Zapit2um]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

The title says '59. Perhaps he was mistaken on the model number.

Thanks!

 

[kfa4303]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

These old FD/E models are great motors and easy to date. I have a '66 20hp myself, which is an FD-20 a '65 is an FD-19, '64 is an FD-18 and so on. You'll want to run 24:1 fuel oil mix along with Champion J4C or J6C spark plugs on your particular models. If you had a post '64 models you could use 50:1, but I always err on the side of caution with these old girls and use a little extra oil. While I could run my '66 motor at 50:1, I perfect to use around 32:1. It makes a little puff of smoke on start up, but otherwise burns pretty clean and provides a little extra security.

 

[Zapit2um]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

Ok.. I bought the 1959 Johnson and yanked the lower unit off and installed it on my 1960. It went quite smoothly and fit perfectly. The question I have now is what type of lube oil is recommended for the lower unit? On the side of the lower unit it call for "hypoid" I believe thats what it say's anyway.

 

[kfa4303]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

Hello again Zap. You'll want to use 80-90w hypoid, outboard gear lube. You can find it at any boat store and many auto stores. One quart will be enough to refill the gearcase several times. You'll also want to get a small hand pump, which they should sell right by the oil itself. Here's an example. There are many brands, but they're all about the same. Also, be sure you only fill from the bottom up and replace the white crush washers each time.

 

[Zapit2um]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

Fill from the bottom up huh? How would you replace the cap on the lower unit without it all leaking back out? Just curious..

 

[Xcusme]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

Well, after you fill the lower unit:
1 Replace washer on the Top screw
2 Re-Install Top screw
3 Remove Bottom fill pump
4 Replace washer on Bottom screw
5 Re-Install Bottom screw

You will loose a few drops of fluid when you remove the Bottom fill pump, but since the Top screw is installed, vacume prevents the fluid from running out of the lower unit.

 

[kfa4303]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

Only a small amount will leak out of the bottom, especially once the upper screw is tightened down. If you fill from the top down, you'll have lots of aire bubbles. The same holds true for all makes and models of outboards. You ALWAYS fill from the bottom up until fresh oil comes out of the upper opening. You then replace the upper screw, remove the pump and quickly replace the lower screw. You will get a small blob of oil that may come out, but it's inconsequential. Here's a handy vid.

Changing Gearcase Lubricant on Evinrude and Johnson Outboards - YouTube

 

[Zapit2um]

Re: Are Johnson 1960 18hp Seahorse & 1959 18hp Seahorse parts interchangable?

I gotcha! Thanks for the help!