1957 Johnson 3 HP - Model # JW13 - issues while running

Bonecrusher1 · Sep 5, 2011

Hi - new to posting on the forum...I have a 1957 Johnson 3HP - model #JW13. This engine has been in the family for 30+ years...stored in a barn for the last 20 years. After cleaning the cob webs off the engine; I did the following:
1. Removed gas from tank (or should I say varnish)
2. Replaced spark plugs
3. Added lower gear case oil
4. Clean carb (w/carb cleaner - did not use rebuild kit)

The engine ran strong!! (after adjusting the low/high speed idle ajustments).

I ran this engine several times around the lake; about 3 tanks of gas.....this engine would start with just a simple pull....

Now....it is hard to start....and I think missing at both low and high speeds. At high speed, it will run rough, then clear up and run beautiful for a second....return to running rough....

I'm thinking it must be electrical....I'm off to the store to buy a spark tester.....can points/coil cause to run rough then clear up for a second and run great?

The motor ran so good....I know it wants to run again!! Thanks for any help....

lindy46 · Sep 5, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Well, check spark, especially once motor is warmed up. A coil can intermittantly fail once it warms up, but I suspect a carb problem. I'd invest in a carb kit and do a proper rebuild. Make sure to remove the core plug on top of the carb and clean the idle circuit beneath it.

oldermotors · Sep 10, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

I have just come into one of these motors and am very interested in what you will do to make it run. Mine was garage stored and not run for about 10 years. I haven't tried to run it yet, but was told by the marina guy that it would be about $250-$300 to fix up. I would love to do this myself and would appreciate any pictures or tips you can be provide. I look forward to your posts and will be following!

freddyray21 · Sep 10, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

if the coils have never been replaced they most likely need to be. A coil can be cracked and worn out and still have spark for a little bit. Case in point. This motor had spark and it ran for a little while when I first bought it.

1946Zephyr · Sep 10, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Awww come on freddyray those coils are just getting broke in.

LOL just kidding. Yea, check your coils out. On that model, just remove the ring on top of the flywheel and the thin aluminum plate under it and you'll see two inspection holes where you can easily see your coils. If yours look like the ones in freddyray's picture, then you need to replace them and I highly recemend you do the wires along with them.

oldermotors · Sep 11, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

OK - Thanks. That looks great. I haven't got mine apart yet. Question: Are these parts readily available or do we need to write to Johnson or what? I'll try to start them in a barrel in a couple weeks and see if they come up.

1946Zephyr · Sep 12, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Anyone who sells OMC parts will have them and that includes this site. These coils were used on twins and singles from 1951, on up till about 1974, so yes they are available. Same goes for the points, condensors and impellers.

kfa4303 · Sep 12, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Hi oldermotors. You can still readily get ponits for that old motor. In fact, you can get most, including the coils right here at iboats. Just click on the Marine Store tab in the top left corner. NAPA aslo sells Sierra barnd replacement parts too. You may have to order them, but they ususally show up next day....for FREE.

nwcove · Sep 12, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

easy tune up for that motor.....dyi at half the cost the shop wants. and like others have said, parts are easy to get! do one repair at a time , take plenty of pics for your own reference, ask lotsa question here......and dont forget to order an impeller when you order other parts.

Bonecrusher1 · Sep 12, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Update om my 3 HP Johnson: installed carb rebuild this week....same issues, so next I plan on replacing
coils and tune up kit. I checked the local NAPA stores...they did not have the parts in stock. I found
coils on sale at JMS marine supply online....coils are $17/each.

If I was doing this over, I would have bought the carb rebuild, tune up kit and coils at one time and
saved the shipping.......

I plan on pulling the flywheel later this week.....

Will keep you updated......

oldermotors · Sep 13, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Awesome! I am a little more optimistic on this tune up after hearing from you guys. I'll take some pics from mine as well and post them in a couple weeks. Good luck Bonecrusher1! Looking forward to hearing the results.

oldermotors · Sep 17, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Hey Guys,

OK - I couldn't wait to get that motor apart and take a look. So, here are the pictures. The engine here looks to be pristine! I was surprised! For the life of me, I could not get that nut off that holds the motor cover on above the dang coils, but I did get some good pictures. A couple things I noticed: 1) it looks like the coils are covered by a black plastic cover. Does that mean they are good, or should I really try to get in there and get those off?
2) as for the magneto gaps - I see that one of the magneto points has a gap and the other magnets are together. Will this matter? Seems like there should be gaps on both points.

Otherwise, all the wires, screws and connections look pretty darn good. Probably just have to get that gap adjusted in the magneto points and then try to fire it up.

Whaddya think?

HighTrim · Sep 17, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Impact wrench will pop that nut off instantly, short of that you will need a strap wrench to hold the flywheel while you use a breaker bar and socket.

To remove the flywheel itself you will need a harmonic balancer puller.

Those coils have been replaced though, not original.

Im not really going to get into magneto theory here, but you should google it to get some reading so that you understand the theory and terminology. Will help you when troubleshooting your motor.

The point gap is 020, you will need a feeler gauge for this. They may first need to be dressed (filed with points file) and cleaned with acetone. If the points are beyond cleaning, they will need to be replaced. The condensors are the least likely culprit, but come with a tune up kit if you end up going that route.

BonairII · Sep 17, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Def replace the points, condenser, and coils while your in there. No sense in cleaning up the points when they are cheap to replace. The peace of mind is worth it. I know many people just clean them up instead of replacing them, but I learned the hard way that cleaning 'em up doesn't always work. JMO

freddyray21 · Sep 17, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

I don't think I have replace two sets of points in my entire life. They just rarely go bad. If you do want to go ahead and replace them. The condensers will be a definite replace.

lindy46 · Sep 17, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

oldermotors said:
Hey Guys,

2) as for the magneto gaps - I see that one of the magneto points has a gap and the other magnets are together. Will this matter? Seems like there should be gaps on both points.

Whaddya think?
View attachment 114251 View attachment 114250 View attachment 114252

Yeah those points should be gapped to .020" when they are in the middle of that inspection window. As mentioned, I'd use a point file or some 400 grit emery paper on them first to clean them up. Coils "look" ok, but that doesn't always mean they are ok. Clean and regap the points and check for spark before removing the flywheel.

1946Zephyr · Sep 17, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Don't replace those coils. They're already brand new. They don't usually fail, until the insulation cracks and with the new coils they sell now, the coating is so much better than what the originals used. The only coils I ever seen fail are those originals with the cracked coating. Otherwise these coils are pretty tough.
I think if you just clean up the points and replace the condensors, you'll be back in business. I would check the spark plug leads though. Often times when people replace the coils, they just shove the old wires into the new coils and often times conectivity is lost. I rarely re-use my old wires on a new set of coils, but if I do, I trim off about 3/8" off each end and make a fresh new connection for the coils and spark plug boots. While you have it apart, check and make sure the coils are perfectly flush with the machined bosses on the mag plate. Mis-alignment will affect the spark by a lot.

Steve A W · Sep 18, 2011

Re: 1957 Johnson 3 HP - Model # JW13 - issues while running

Here's a link to a tutorial on Your tune up;

http://www.maxrules.com/fixtuneitup.html

Good Luck
Steve A W

1957 Johnson 3 HP - Model # JW13 - issues while running

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