Johnson Seahorse 3hp

[Chris52796]

I got a 3hp Johnson Seahorse model number is jw-15 and need to get parts for it but i found a person on Craiglist with the same motor for the parts but its a jw-18. Are the parts different for each model number?

 

[1946Zephyr]

Re: Johnson Seahorse 3hp

Pretty much everything should be the same. JW-15 is a 1959 model and JW-18 is 1963. These were virtually the same, from 1952 till 1968. Which particular parts are you needing?

 

[Chris52796]

Re: Johnson Seahorse 3hp

Well I got scammed on craiglist on the motor. He had no gas in it for an excuse, so I bought it for $80 and i tried to run it and would not even run. I spent $90 of parts to fix it and still no, I found a jw-18 for $50 on craiglist for rapair and i think i can switch the parts over to get it running.

 

[1946Zephyr]

Re: Johnson Seahorse 3hp

Why is it not running? No spark? No fuel? Getting the $50 motor is a good deal, but I would just replace the parts thats giving you the trouble. It's likely to have bad coils and needs a carb rebuild. Shoot, go ahead and purchase the other motor and you can easily have two good running motors in the end. This little JW's are good responsive motors and are pretty easy to coax back to life. We'll help you get the two running.

 

[nwcove]

Re: Johnson Seahorse 3hp

do the basic compression test on both,and like zephyr said.....you will probably end up with two nice working motors. then maybe sell one and get the one you like best for next to nothing.

 

[1946Zephyr]

Re: Johnson Seahorse 3hp

You came to right place, if you want help making them both run. A lot of guys here are pretty partial to those little guys.

 

[Chris52796]

Re: Johnson Seahorse 3hp

The compression is at half what it's post to be at. I got it to back-fire a few times but thats with starting fluid spray. I replaced the water pump, rebuilt the carb and put new coils in. But with the $50 motor I might switch the parts from mine to the new one because it looks better.

 

[nwcove]

Re: Johnson Seahorse 3hp

You came to right place, if you want help making them both run. A lot of guys here are pretty partial to those little guys.

i have a 62 lightwin......im sure it fell off the back of a truck...and was run over.....the gearcase has been welded, the skeg is a piece of galvanized pipe, it looks like hell, but i have run that motor all day long trolling, and never worry about it . those motors are almost bullet proof!! and definitely worth putting some time and a few bucks into.

 

[1946Zephyr]

Re: Johnson Seahorse 3hp

Cool. I have a 1970 Lightwin that looks almost like new. I rebuilt the powerhead for a guy about 3 years ago, but hasn't paid me for it yet, so it's safe to say that it's mine now.

Chris, you might possibly have the spark plug leads crossed. The front coil feeds the top cylinder. Also, you need to make sure that your coil faces are perfectly lined up with the machined bosses on the mag plate. Did you replace the coil wires when you replaced the coils? Most often, people don't and just connect the old wires with the new coils. Often times, connection will fail here. If you do, use the old wires on the new coils, it's best to trim off 3/8" off the wire and twist it in the coil. Of course, when you do this, you'll need to loosen up all the securing hardware and slide the wire forward, to equal what you trimed. Then you'll want to trim off 1/4" from the spark plug end and re-assemble the boot assembly.

 

[nwcove]

Re: Johnson Seahorse 3hp

The compression is at half what it's post to be at. I got it to back-fire a few times but thats with starting fluid spray. I replaced the water pump, rebuilt the carb and put new coils in. But with the $50 motor I might switch the parts from mine to the new one because it looks better.

what is the comp #'s 60 psi is still ok, dont give up on either motor....unless there is a comp issue, even then a head gasket (8$) may cure it,or even seafoam might help.
there is so much knowledge here in this forum, that im sure if you post pics, ask questions, go through the steps of trouble shooting, you can have both motors running quite well.

 

[1946Zephyr]

Re: Johnson Seahorse 3hp

Yea, I had a nice running old JW-14 last year, that had 60 psi in each cylinder. Those pistons are tiny, so don't expect much more than that.

Yes, please post some pics. I bet we can help you get both of those motors running like a top and make a professional outboard mechanic out of ya.

 

[Chris52796]

Re: Johnson Seahorse 3hp

Thanks for the info! I am not sure what you mean about aligning the coils with the mag plate. Any chance of getting some instructions to do this?

Also, I did reuse the old wires. We do have spark and it seems strong. I did swap the plug wires to check but it still didn?t start.

We tried to start it with starting fluid and still nothing but a backfire every once in a while.

Thanks!

 

[Chris52796]

Re: Johnson Seahorse 3hp

Thanks for the info! I am not sure what you mean about aligning the coils with the mag plate. Any chance of getting some instructions to do this?

Also, I did reuse the old wires. We do have spark and it seems strong. I did swap the plug wires to check but it still didn?t start.

We tried to start it with starting fluid and still nothing but a backfire every once in a while.

Thanks!

 

[Chris52796]

Re: Johnson Seahorse 3hp

ah sorry for the double post
i'm new to this site

 

[1946Zephyr]

Re: Johnson Seahorse 3hp

It's okay. It happens.

Yea, on those coils: you'll see a neatly machined area, right under the fronts of the coils, on the mag plate. The face of the coils is supposed to be lined up with that, as close as possible. This will give the perfect clearance for the flywheel. The red arrow points at the mounting bosses on the mag plate. Use a straight edge to line them up with the machined surface.

 

[Steve A W]

Re: Johnson Seahorse 3hp

And Please don't use starting fluid on it.
It doesn't have any lubrication in it and can kill a good motor.
Good Luck with it.
Steve A W

 

[1946Zephyr]

Re: Johnson Seahorse 3hp

Yea, good point. Always use fuel mix in a spray bottle.

 

[lindy46]

Re: Johnson Seahorse 3hp

Try spraying a little premix directly in the cylinders - "prime the pump" so to speak. I bought a 3hp Lightwin this summer and she wouldn't come to life until I did this. Now she runs like new.

 

[Chris52796]

Re: Johnson Seahorse 3hp

Ok, thank you 1946Zephyr! theres mistake with the coils that you talked about ill try it out and let you know what happens :]

 

[Chris52796]

Re: Johnson Seahorse 3hp

The scratches on the cylinder walls are minimal from what I can see. No gouges, just scratches.



The tank was bone dry when we got it, I added fuel that I have been using with my chainsaw that I know is good. So I would doubt water in the gas.



We haven't put the rebuilt card on it yet, I could try to put it all back together and see how it goes. It doesn't appear the engine has been apart in a long time. Most of the gaskets were delicate, most with white paint on them.



I included a couple photos. J
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