Super Seahorse cooling question

imported_hippie

Seaman Apprentice
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Jul 12, 2006
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32
Hi all;
I will be quite honest and say that I know very little about boats and am not much of a mechanic either, however; I have fixed my vehicles without a clue just by searching the web and using manuals.
I just purchased a Johnson Super Seahorse 35, from the research I have done, I assume it is about a 1959 - 1963 (an oldie), I have got the engine to run and am testing it in a large barrel, my question is this;

When it is in neutral I see a large amount of splashing and thrashing in the bucket,,, is this the water being pumped to cool the engine, it seems to be coming from the hole below the intake for the water,,, however; I dont see any coming out of the exhaust at the top of the leg. is this normal, I didnt want to run it to long without being sure,,, I tried to talk to a boat mechanic and he told me to take it out to the lake and see if it runs???? said an engine of this age isnt worth putting any time or money into???.
any help would be great, thanks in advance and sorry for the long post.
 

Rick K

Petty Officer 1st Class
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Oct 6, 2003
Messages
235
Re: Super Seahorse cooling question

From what you describe, no, it's not normal. SO DON'T RUN IT!!! I mean the lack of water coming out of the engine, that is. Sounds like the impeller ain't circulatin' water. Might as well replace it, it's toast...

My first thought on determining if the motor's any good, is to do a compression check. Anything 100 and above, with both cylinders within 10% of each other is good.

Also do a search on "awakening" for Awakening an outboard motor. Basically, that gives you the steps involved for getting your motor back on track.

That motor is an absolute beast. A die hard. It pushed my 15' Starcraft around like a rocket.

If ya got good spark, gas, good compression, then ya got a good motor.

I also see this is your first post. Welcome to iboats. If you go up a few posts, and read my post on 18HP Stumped, you see how very quickly the folks here are willing to help. And you'll also see the results of MY bullheadedness, and, you'll learn what to do if ya ain't got no spark!!!

Read up on stuff and do a lot of research, and you'll learn everything you'll need to know to have a great time on the water!

Good luck!
Rick
 

jimmbo

Supreme Mariner
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May 24, 2004
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13,638
Re: Super Seahorse cooling question

The 35 was made in 1957, 58, and 59. In 58 and 59. A model number would reveal which. In 58 and 59 there were two different types, one version had a thermostat and one that didn't'. This is significant because there were major differences in cowlings and cooling systems. The ones with a thermostat had water tubes to send water back to the water pump and did not discharge much water out of the idle relief till the stat opened, even then I do not recall much water spraying out of my dads motor.

Is the thrashing you see in the bucket just the exhaust rising to the surface?
 

lark2004

Lieutenant Junior Grade
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Messages
1,080
Re: Super Seahorse cooling question

The hole at the top of the leg is just a relief hole. Not the main exhaust outlet.

The main exhaust is the big hole in the 'fin' behind the prop......below the water inlet. So the thrashing in the bucket you are seeing is probably just the exhaust.
 

tashasdaddy

Honorary Moderator Emeritus
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Messages
51,019
Re: Super Seahorse cooling question

if you can't find awakening a sleeping outboard, email me, and ask for it. like they said it is bullet proof, and the mech you talk to is an idiot. i have a 55 15hp rude i use all the time. also ask for carb adjustments.

tashasdaddy@comcat.net.
 

imported_hippie

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Jul 12, 2006
Messages
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Re: Super Seahorse cooling question

thanks to everyone with their replies, I found the awakening article very informative, I guess my first step would be to find the exact year of this engine so I can get a manual. is there any sites that will allow you to download a manual rather than have it shipped out, I do not have a problem paying for it, I just dont want to wait for three weeks for it to get to me.

thanks again;
 

tashasdaddy

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Re: Super Seahorse cooling question

the best manual is the OEM available @ kencooke.com the click manuals johnson will need model #. no down loads.
 

Rick K

Petty Officer 1st Class
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Messages
235
Re: Super Seahorse cooling question

You won't find a downloadable manual, hippie. If it turns out to be a '59, I have the original parts manual - somewhere. I'd be happy to send it to you, I really have no use for it.

Rick
 

imported_hippie

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Re: Super Seahorse cooling question

Rick said:
You won't find a downloadable manual, hippie. If it turns out to be a '59, I have the original parts manual - somewhere. I'd be happy to send it to you, I really have no use for it.

Rick

ok, the model number is a RDS-21, I found through looking on this site that it is a 1959 Johnson Super Seahorse,
do you know is this the model with the thermostat or not?
thanks again for the help.

Hippie
 

Rick K

Petty Officer 1st Class
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Oct 6, 2003
Messages
235
Re: Super Seahorse cooling question

Hippie,

Now that's a darn good question. I think the thermostat started in '59. And, I made a mistake - mine was an RD-19, which is a '57.

Whatcha do, is click the Marine Store button at the top left of this page, then engine parts, then go from there. You'll find what ya need.

You really need that manual though...
Rick
 

imported_hippie

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Re: Super Seahorse cooling question

you bet I need the manual, after this thread I will order one on line, you know how it is, just like a kid with a new toy, I want to get this thing out on the lake without waiting for 3 weeks for a manual to arrive,
Soooo, I kind of looked around the forum and took a little advice on getting to the water pump,,, " found it", I did see something wierd though, from what I can tell there are two lines that go to the pump, I am assuming one is for intake and one is for discharge, or would they both be for intake? the propellor seems to be in there very tight? shouldnt this think move freely? when I say tight I mean like squished at the sides tight?
 

jimmbo

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Re: Super Seahorse cooling question

The RDS-21 was the 1959 Super Sea Horse and it has the thermostat. 1958 was the first year they had a stat on the top of the line 35hp and on all V4 50hp models

Check this site http://www.old-omc.de/index2.html
 

jimmbo

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Re: Super Seahorse cooling question

As I said before, models with the thermostat had two lines going to the water pump. One is supply to the engine and the second is a recirulating pipe which returns water to the pump until it is hot enough to open the stat
 

imported_hippie

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Re: Super Seahorse cooling question

thanks for the reply's,can someone tell me where the thermestat is on this unit, would it have access from the top of the engine and have three screws holding a cover down on it?
I am thinking this is the problem or a blockage in the main lines, the propellor looks to be brand new?
 

tashasdaddy

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Re: Super Seahorse cooling question

i believe that is the one you are looking for. take the stat on and using a candy thermo suspend the stat on a pot of water and heat, don't let the stat touch the pot. (wire it to a big spoon handle or something and hang it ing the pot) note when it starts to open and when it is fully open. post back. my manual only goes to 30 hp.
 

jimmbo

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Re: Super Seahorse cooling question

Before running it, since it is an older motor, it would be good practice to replace the water pump impeller and possibly the water pump housing. Old impellers get hard and lose flexability falling apart, impeeding the performance of the pump
 

imported_hippie

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Re: Super Seahorse cooling question

thanks for the reply's I have removed the top housing on the engine, with expectations to find a thermostat, however, all I found was a small spring with a piece of rounded beige plastic at the top, looks to me like a pressure switch? mabey the spring is pressure rated, I do not see anything that looks like a thermostat
 

imported_hippie

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Re: Super Seahorse cooling question

just an update, this spring and small cap seem to look like they are from the thermostat kit listed in the parts area here, I must admit I was thrown off since, I was looking for a thermostat similar to the one in my car. I dont know if he removed the thermostat or if I am still looking in the wrong area. thanks again;
 

jimmbo

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Re: Super Seahorse cooling question

The thermostat should be the 1st thing you see once the top housing is removed. It is made of brass or copper and rests in a plastic housing. the spring and disk you mention are underneth this housing and are there to control the flow of water back to the water pump. When the stat is closed water pressure forces the disk off its seat, allowing water to return to the water pump. Once the stat opens, the water pressure drops and the spring pushes the disk back on its seat permitting the water pump to draw in new cooling water.
It looks like the stat was removed.
 

tashasdaddy

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Re: Super Seahorse cooling question

you need to replace the stat, because running without it runs cold adding to carbon build up and poor performance.
 
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