Johnson 1956 15HP Will not start

[Miller4519]

I recently purchased a 17' jon boat that came with a 1956 Johnson 15HP outboard that I can't get started. It would turn over when I squirted some gas mix into the carb, but not run in the barrel. I first cleaned and rebuilt the carb 4 times with no luck. I replaced the fuel lines including the primer bulb line that goes to the fuel tank as well as the fuel pump. I get fuel in the carb bowl with no issue everytime I try to turn it over. I then decided to replace the coils, condensers, points, and spark plug wires. It gets spark to the plugs but it won't turn over now, even when I squirt some fuel into the carb. Compression is 95 in the top plug and 100 in the bottom.

I now have 50 hours in this motor and its still not running and now wont turn over at all after my ignition work, which I've taken apart several times and adjusted until I finally got spark. Can the motor flood and not burn the fuel with carb full choked? Any suggestions?

 

[fhhuber]

Needs for an engine to run:

Compression (95 psi is not great but enough)
Fuel (Just getting to the carb doesn't mean it gets in the cylinder)
Fuel mixing with air in proper ratio (too much fuel works but fouls plugs)
Properly timed spark

You probably should be using 25:1 fuel-oil mix until you get it figured out.

What you need to find out is if the fuel-air mix is correct (close enough) at the cylinder. if the intake valves are not working correctly your engine isn't going to run. It might pop a few times if you spray some fuel down the carb.

Pull the plugs and disable the ignition. Put a piece of paper over the carb air intake. pull the starter cord firmly to spin the engine several revolutions. The engine should try to pull the paper in, and not significantly blow it away. if the paper is rapidly being pulled in and blown away from the intake, your valves are not working.

Reed valves are not terribly difficult to fix. Reeds that don't seal can drive you nuts.

 

[Miller4519]

Thanks, I will do the buisness card check on the carb tomorrow after work. I have two shop manuals I picked up and have skimming through and saw that check. I should also point out that one of my coils was bad when I checked it with my meter. Can the motor still turn over with one bad coil? Also, any idea why it won't turn over now after I put new coils on but would with the old coils?

 

[oldboat1]

Replace the impeller or risk breaking up an old one (clogs cooling passages).

Wire has to be 7mm wire core, not automotive wires. Assuming you have coils with spikes, the wire needs to be twisted in place in solid contact with the wire core. The same is true with the connectors in the boots (spring connector spike has to be in contact with the wire core.) Chances are, the new coils are fine -- would rule out other issues first.

The point gap is .020 and contacts have to be very clean (use alcohol, lacquer thinner, or acetone). Coils have to be mounted perfectly flush with the mounting bosses. (Check the flywheel magnets while you are at it, just to be sure.)

You can test for spark during magneto set up by turning the flywheel clockwise by hand. With plugs out, use an open air spark tester adjusted to about 1/4". Put the flywheel in place over the key, but don't torque it down. Spin the flywheel clockwise sharply using both hands while checking spark tester. (Make sure the tester has a good ground.)

24:1 is good for mix. Some use 16:1. After spark is established and flywheel torqued to spec, run with Champion J4C plugs gapped at .030.

 

[Miller4519]

I did the paper test today and the carb sucked the paper in. It did not appear to blow it back out. Also no fuel on the paper. I will post a picture later (once I figure out how to) of the carb. There is a small hole on the side that seams odd. When I was cleaning it after the carb dip, I blew carb cleaner in it and it came out the nozzle inside the carb. Just odd that there is a hole there. I also picked up an open air spark tester and no spark. I get a small spark when using the spark tester with the light bulb in it. So I took it apart again and took out everything in the ignition and cleaned it with electrical contact cleaning spray. There was some grease that had gotten on the bottom of the points that I missed. The rookie I am, I put some grease on the crankshaft and it got on my my ignition parts. Everything is now clean but still no spark, so looks like I'll be making more adjustments to find what I did wrong. I got 7mm metal core spark plug wires from Napa. I did a check with my meter from the spark plug boots to each wire coming out of the coils. The longer wire gave a reading of 10.4 and short wire was 10.35 so cables are good.

 

[oldboat1]

best bet is to clean the points yet again, and check (reset) the gap. Should remove the flywheel anyway and clean the shaft with some acetone or lacquer thinner -- want no grease on the shaft. Make sure the key is in place in the keyway, and the flywheel fully set down over the key -- should be using an oem key made for your model.

 

[Miller4519]

No Title

 

[Miller4519]

Sorry for the delay guys. Work has been keeping me busy. I promise to update this post all the way to the end. I could not get a spark after numerous adjustments to the coils so I broke down and ordered thr coil ring and timing tool from www.richardsoutboardtools.com. Hopefully I can get my spark back.

 

[Crosbyman]

http://www.youtube.com/watch?v=ga1Cjymj6ms&feature=youtu.be

worked for me

 

[oldboat1]

You might revisit your coil tests and wire assembly. As the coils are new, it's not likely they are bad. The test between the plug boot (i.e., the connector) and the coil ground wire should give you 5000 or 6000 ohms on a 1K resistance scale. Yours is apparently higher than that, and may indicate that you have a poor connection -- maybe some rust or corrosion on the spring connector in the boot. It's possible that connection might be presenting problems.

It can't hurt to clean up that connector in the boot with a phillips screwdriver, and see if spark is restored on your spark tester.

The other end (coil end) of the plug wire can also be a problem -- has to be twisted into/on to the coil spike, with the metal core in solid contact with the spike.

 

[Crosbyman]

1K.... x 5000 == 5000K ....===> 5,000,000 OHMS ....I think


​1K scale x 5 - 6 =====> 5000 or 6000 ohms

 

[oldboat1]

Doug Penn instructions are good: https://www.youtube.com/watch?v=KT8rk5QWgS0

 

[Miller4519]

Thanks for the videos. I'll be watching them soon. So I replaced eveything again with another brand new set, but this time with OMC parts. I wasn't sure if that Sierra stuff was the problem. I got a nice blue spark in the bottom cylinder and no spark in the top. I will adjust it tomorrow after work and hope I'm done with the ignition. FYI, that coil ring is awesome!

 

[Miller4519]

No Title

 

[Miller4519]

I got it to fire again and it sounded beatuiful! My issue was that I rewired the coils the same way the last guy had them and found they were wired to the wrong points. After watching a video on the timing tool, the guy referenced the points are always on the right side of the coil when making the adjustments. So my issue now is fuel delivery. It runs on what I spray into the carb, but won't stay running. There are two holes on the carb that I believe are missing the lead plugs, so looks like I will be raiding my tackle box next for some lead sinkers to hammer in there. Here the video for the tool.:
Watch "Setting ignition timing with a timing fixture on Evinrude, Gale and Johnson motors" on YouTube
https://youtu.be/eNK2TEeQQv0

 

[Miller4519]

I finally got this thing running, but still some ways to go. I left the spring out of the starter solenoid. Not sure if that was it, but the carb is now working after putting the spring back in and tighting all the screws again on the carb. Thank goodness I read repair manual again. I let it run for about 5 minutes in the trash can and it would not restart after turning it off. Let it sit for about 15 minutes and it started again. The top cylinder spark plug was loose and I need to rethread it. My Heli-coil kit will be here today

 

[Miller4519]

It now starts evey time. What a relief to have this up and running. Lots of smoke with the oil mix being too heavy. I'll have to tweak my mix to the right amount. The tune up is now 100% complete with the water pump now done too. Last thing left is to get the pull start fixed without having to rely only on the starter to get her purring. Thank you for the help guys.

 

[oldboat1]

Run a 24:1 mix on that motor. Glad to hear you are up and running.

 

[Miller4519]

Okay, I'm back to not starting again. It was running every push of the button and suddenly nothing. So I changed the head gasket and a new head since I didn't want to trust the heli coils for the spark plugs. I also put a glass fuel filter on before the fuel pump. I checked the flywheel key and torqued to 40lbs. Each plug has a giant blue spark and 85 psi. I tried to start again and it sputtered and then nothing. So I took the carb off and cleaned it. It started right up after I put it back on. I adjusted the idle screw and ran for about 5 minutes. Turned it off and started 3 more times until it sputtered out. I think I had the throttle handle to close to start. It then would not restart. There was a lot of water coming out the exhaust when it was running with the new water impeller. Could it be the exhaust plate?

 

[Miller4519]

So my issue was a simple fix. My starter is activated by a push button. I was holding that button down too long and flooding the engine. A 1/2 a second push starts the motor everytime. My first water cooled outboard... Now time to adjust the high/low speeds on the carb. I can say these vintage outboards are addicting to work on.