'58 Johnson SuperSeahorse Questions

[CATransplant]

I just bought a boat with this engine on it. Previous owner reports that it runs perfectly, but has not run it for a couple of years. I know...pig in a poke. I've ordered a service manual, and will be cleaning the carb and replacing the impeller before I try it out.<br /><br />I have a couple of questions, though, that I can address before then, so I don't have to waste time with those issues when I could be working on the motor:<br /><br />1. Since this is a 1958 motor (Model RDS-20), I'm curious about battery voltage. Is this a 12-volt system? I know some cars were still 6-volt back then.<br /><br />2. The key for the ignition switch on the boat is gone. I know that these key switches are different from an automotive ignition. Can anyone tell me what the difference is. I'm going to replace the keyswitch with a plain switch(es) that doesn't require a key.<br /><br />3. The fuel hose for the tank is stiff and cracked and I want to replace it. Anything I need to know? I'll use the connectors from the original hose. I have an original Johnson tank, but it may be from a later period.<br /><br />This is a great place, and I'm sure I'll have other questions later on. If I can ever answer any, as I learn, I'll certainly do so. Thanks for all the help!

 

[CATransplant]

Re: '58 Johnson SuperSeahorse Questions

Oops. Sorry. It's a 35 hp, so you won't have to look up the model number. My bad.

 

[DHPMARINE]

Re: '58 Johnson SuperSeahorse Questions

12 volts should be okay,but examine the starter itself.It will be stamped with the voltage.<br /><br />Look at the ignition switch cylinder.It may be stamped with a number,like KFxx.Take that number to a dealer,he can probabaly sell you a key.<br /><br />If you have a dual line hose,your dealer sells it.If you have a single line hose,buy a new hose assembly (new hose,primer bulb,and connectors on each end.<br /><br />Hope this gets you going.<br />Make sure you have compression and spark before going too far.<br /><br />DHP

 

[Paul Moir]

Re: '58 Johnson SuperSeahorse Questions

The 12 volt starters are under 4" in diameter (about 3-1/2" or less). Unless someone's been switching parts, yours ought to be a 12v system.

 

[CATransplant]

Re: '58 Johnson SuperSeahorse Questions

Thanks for the assistance. I bought a new ignition switch, and have it all wired up correctly now. I'm just waiting for the weather here to warm up a little before attempting to fire up this 35.<br /><br />The new hose assembly was a snap to find, since it's a single hose system. The tank is spotless inside (thanks to that oil in the gas), so I'm not anticipating much trouble there.<br /><br />I've got my fingers crossed, and will let you all know what happens when I try to fire it up. In any case, a new impeller and a change of lower end oil is in the works, but I just don't want to spend a whole lot of time and money until I hear the thing run, at least briefly.

 

[Paul Moir]

Re: '58 Johnson SuperSeahorse Questions

While you wait for better weather and before you fill the system with gasoline, try testing spark. You can do this with or without the spark plugs in and you don't have to set up a bucket of water, etc. You should be able to draw a longer spark than 1/4" of each wire if all is good.<br />I only mention it as it's often a source of trouble on these old engines. Repairs to it are reliable and easily/inexpensivly done.

 

[CATransplant]

Re: '58 Johnson SuperSeahorse Questions

Paul,<br /><br />I thought of doing that, but several people have told me that I shouldn't even crank the engine without having the lower end in water. While I'm planning to replace the impeller anyhow, if it is still working, I might do some of the engine work before replacing it. Will cranking the engine to check compression and spark harm the impeller or pump housing?

 

[jfm1]

Re: '58 Johnson SuperSeahorse Questions

Do the compression and the spark test and then you know what you have to work with motor wont start doing these test won't hurt anything and your changing the impeller anyhow let us know what you find

 

[Paul Moir]

Re: '58 Johnson SuperSeahorse Questions

I agree completely - turning the engine at cranking rpms will in no way harm the impeller.

 

[CATransplant]

Re: '58 Johnson SuperSeahorse Questions

Thanks so much, you guys. I'll do that, and you're right. If there's no compression, I'll be dumping the motor. No spark, and I can just afford to fix it. I'll have to do this next week, since it's so darned cold up here right now. If I'm outside working, my fingers freeze right up, and I can't do anything with gloves on.

 

[CATransplant]

Re: '58 Johnson SuperSeahorse Questions

I just wanted to thank those who helped me with my questions. This weekend, I put a new impeller in the RDS-20 (easy job). I put in a pair of new plugs, cleaned out the float chamber in the carb and the glass bowl on the fuel pump, and changed the oil in the lower end. That's all I did to this '58 Super Seahorse that has been sitting for three years.<br /><br />I connected the cable from the external box, hooked up a battery, plugged in the fuel line from a tank full of fresh fuel, and pumped the bulb a couple of times. Oh yeah, the motor was sitting in a Rubbermaid Husky trash can with water halfway up the long shaft extension.<br /><br />I pushed the choke button and turned the key. Vroom! After about 30 seconds of rough running, the engine settled down to a nice fast idle. Once it warmed up, it was spewing water nicely.<br /><br />Now, I'm ready to put the thing in the lake and see how it works in the real world. It's amazing to me that an outboard that is almost 50 years old can be brought back to a useful life so easily. These Johnson's are terrific!<br /><br />Again, thanks to those who offered help on my questions.

 

[rwise]

Re: '58 Johnson SuperSeahorse Questions

time to go fishing now! happy boating and may your 58 johnson be as reliable as mine!