1958 Johnson Seahorse 5 1/2 HP Tune Up

[Marcaronio]

I am new to the forum and outboards in general. I have always wanted to learn more about engines and also was looking for a cheap way to have fun with the wife and kids on the Weeki Wachee River near my home. I found a 9ft Seaworthy inflatable for $100 and a 1958 Johnson Seahorse 5 1/2 HP outboard for $70 on craigslist. The motor is running but is in rough shape. This thread will be used to document the tune up of this motor and to hopefully get help when I get stuck.

The first thing I did was to build a stand based on some plans I found on the forum:

Then I set out to find information on the motor and instructions on how to give it a tune up. I found the following website dedicated to the tune up of what appeared to be the same motor that I have: http://www.outboard-boat-motor-repair.com/johnson/default.htm

I used the model reference page (http://www.outboard-boat-motor-repa...de Johnson 5.5 HP 1954-1964 Model Numbers.htm) to locate the model number on my transom mount:

To my dismay the model number (CD-25C) was not listed. It appeared my model number was for a 1968 Johnson 6 HP motor. I then looked through the catalogs on the old-omc.de website to try and find my motor and based on the paint schemes and appearance of my motor determined it to be a 1958 Seahorse 5 1/2 HP. (http://old-omc.de/j_1958/seite_08.jpg)

I am guessing that the transom mount had been replaced at some point. From what you can tell is my assumption correct? I would like to be certain before I purchase any parts.

Thanks,

Marc

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

While cleaning up the motor and comparing it to pictures I found online I found some potential problems.

First it appears as though my high speed jet (which is missing the knob) is too long and is therefore not correct:

It is much longer than the low speed jet and can only be threaded one full turn before bottoming out in the carburetor. Is this the correct jet? If not, can this one be used?

Also the tiller handle appears to have been repaired at one point:

The repair appears to be strong however the added material to the bottom is obstructing the motor from being turned smoothly:

The handle also appears to have been replaced and the label is missing. This is a problem as I don't know where to put the handle when starting the motor.

Is there any way I can determine the starting position and label it myself?

One of the handles for tightening the clamps is missing as well:

I can fabricate a new one easily enough.

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

Here are some other pictures of the motor:
FRONT (the panel is not missing, however, the labels are worn off and the high speed knob is missing):

SPARK PLUG AREA (I said I was a newb):

If you would like any more pictures please let me know.

Thanks,

Marc

 

[nwcove]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

welcome to iboats marc, great to see all the pics of your project! since your motor runs, read the top secret files and enjoy the satisfaction of getting your motor to run like it should.
it looks as tho it is a mixture of parts from other motors, stay with it, enjoy the challenge!
if you want pics of similiar model year 5.5 ,s, i have a 56, not working, and a 57 that works great. can post, or email pics of things you may want to see.

good luck!

 

[nwcove]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

welcome to iboats marc, great to see all the pics of your project! since your motor runs, read the top secret files and enjoy the satisfaction of getting your motor to run like it should.
it looks as tho it is a mixture of parts from other motors, stay with it, enjoy the challenge!
if you want pics of similiar model year 5.5 ,s, i have a 56, not working, and a 58 that works great. can post, or email pics of things you may want to see.

good luck!

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

Thanks so much for the welcome! Would you agree that my motor is a 1958? Would I be safe to follow the tune up directions from the website listed above? Do you know how I can identify and label my tiller handle for the start position? Is the longer high speed jet I have ok to use or should I source the appropriate one? Sorry for all the questions!

 

[nwcove]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

the cowl does appear to be from a 58, not sure how to identify the powerhead as a 58? (hope some of the other members jump in here!) if you get yourself a complete carb kit it , it will come with all the right parts. my 56 and 57 both show the start position at 12 oclock (arrow straight up). with that being said, dont pay a whole lot of attention to that tho, once you use this motor a bit, you will just know, without even looking, where to put the throttle, when to choke it, how long to keep it choked....etc etc.

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

I have finished performing the tune-up on this motor! This was my first time ever working on a 2-cycle engine and I learned a lot during the process. I performed the following tasks in this order:

1. Unbolted the head and removed the carbon deposits from the pistons and inside of head. Also cleaned all the gunk out of the water passages and blew everything out with compressed air. Bolted it back on with a new gasket. (i think i put the gasket on upside down. remember this for later)
2. Rebuilt the carburetor with all new gaskets, washers, float and float needle. Also performed the pulse fuel pump conversion.
3. Replaced all ignition components to include the wires and spark plugs. Timed the motor and gapped the spark plugs.
4. Started the motor and it ran well. Was adjusting the jets when I noticed the engine was getting really hot. I shut it down immediately.
5. Unbolted the powerhead from the lower unit and took the lower unit apart to get to the impeller. Found that my impeller was in pieces. Put the new impeller in and cleaned out all gunk from all of the water passages on the underside of the powerhead as well as the lower unit.
6. Replaced the gear oil.
7. Started the motor again and noticed that it is still getting hot.

In the instructions I am following it says, "You should also be able to touch the cylinder head and crankcase with your fingers and not get burnt." This is not the case for me. I can see water coming out of the exhaust when it is running now so I know that the impeller is working. I am worried that the water is not taking it's full path through the engine and is leaking into the exhaust before getting to the head.

I'm as new as new can be to engines let alone diagnosing problems, however, I started thinking it through and here is what I can think to check:

1. Check for leaks or blockage in the pipe leading from the impeller housing to the powerhead to lower unit gasket.
2. Check for leaks or breakage between the water path and exhaust in the powerhead to lower unit gasket.
(i believe the first place the water goes in the powerhead is next to the exhaust manifold, is this correct?) The blue is the path of the water while the red is the exhaust right?
3. Check for leaks or blockage in the exhaust cover.

(i believe the second place the water goes in the powerhead is through the outer jacket of the head, is this correct?) The blue is the path of the water.

I found 1 potential problem. Let me know if you think this could be causing water to not get to the head or even cool off the exhaust manifold cover.

In this picture of the exhaust manifold cover you can see a small hole near the top. Also there is no gasket or gasket material on this cover. Should there be? I can see water coming up out of this hole and boiling while the engine is running.

Is it possible that water is leaking between the water passage on the left into the exhaust manifold because there is no gasket and is being boiled up and out of the hole in the exhaust manifold cover? Water should not be in the exhaust manifold under normal operation correct?

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

Updated the last picture to show the hole in the exhaust manifold cover better.

 

[nwcove]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

both my 56 and 57 have gasket material around the exhaust cover, exhaust pressure could be bypassing and working against the impeller.....and also making the water that is getting to the powerhead extremely hot. the hole in the manifold is a definite problem too, not sure if it would cause overheating tho.

 

[nwcove]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

any progress marc?

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

I ground down the inside of the exhaust cover and filled the hole and low spots with JB weld. After curing for 24 hours I machined the cover flat with a piece of glass and sandpaper. Then I used RTV blue to make a new gasket around the cover and bolted it back on the engine. It has had time to cure so I will be testing it today to see if the hole and lack of gasket was the cause of my overheating problems.

Now I have a new problem. I drained the old gear oil out last week and replaced with new oil. That was before I ran the engine and found that it was still overheating. The old oil came out looking like a milkshake. Water was obviously present in the oil. Well after taking the weekend off I noticed that there was a pool of oil under the engine. I drained the oil again and my new oil looks like a milkshake. I ordered a new o-ring, water seal and sealing rope for the lower unit. Now I cannot test the motor until the new parts get here and I can seal up the lower unit again.

 

[nwcove]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

what is the temperature rating on the rtv blue? those exhaust covers get extremely hot. id focus on the motor issues first, keep some fresh oil in the gearcase as you run it, and deal with the lower end when the motor is working well.

 

[scipper77]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

Make sure the water pick up tube in the lower is installed correctly. It might be possible that the water pump is pumping but the water is running back down and out of the lower without reaching the motor.

 

[scipper77]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

Also, my motor (1961 evinrude 5.5) has the model number stamped on the side of the block (model 5522). This model matches the plate for mine. I can take a pic if you like when I am at home.

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

NWCOVE: Blue RTV Gasket Maker is rated to 500F.

SCIPPER77: I'm pretty sure the pick up tube is installed correctly. Water was boiling out the hole in the exhaust cover. I wouldn't think it could get that high if it wasn't being pumped up there. Maybe it was as steam. I will go take a look at the side of the block now. Is it stamped in the freeze plug?

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

OK, I started it up this evening. The good news is I am getting the hang of where to put the throttle and choke to get it started in a few pulls. The bad news is that it got hot really quickly again. I am wondering if running it in a 5 gallon bucket is the problem. How high does the water have to be in order for the impeller to work correctly?

 

[scipper77]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

I ran mine on a 5 gallon bucket the first time and mine overheated as well. I thought it was my impeller. It turned out the old impeller was worn but not failed by any means. I replaced the impeller and found a deeper bucket.

I would imagine you may have the same trouble as I had.

On the bright side I wonder if the high temps helped to cook off some of the deposits in the motor.

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

I went out and got a taller kitchen trash can and ran it again. It still feels like it is getting really hot. I'm uploading a video now that shows how much water is coming out of the upper exhaust. I really didn't want to take the powerhead off again but it is looking like I might have to. How hot are the exhaust cover and head supposed to get?

 

[Marcaronio]

Re: 1958 Johnson Seahorse 5 1/2 HP Tune Up

Here is the video:
[video]http://s161.photobucket.com/albums/t217/Marcaronio/1958%20Johnson%20Seahorse/?action=view&current=MVI_6032.mp4[/video]