Johnson Outboard Won't Start

[rgballard]

I have a 1956 Johnson 30hp (RDE18C) which I have been working on. So far I have replaced the coils, points, condenser, plug wires and plugs. I have also rebuilt/cleaned the carburetor.

At this point I have not been able to get it running. When I try to pull start it. The first couple pulls don't do much, but it seems to get harder to crank each time I pull. Then by about the 10th pull it has a loud pop from the exhaust.

From reading it sounds like the plugs aren't igniting when they should. I pulled the wheel off today and checked the points the gap wasn't quite right, so i regapped them to .020 and put it back together. This time every 4th pull or so it would have the loud pop from the exhaust.

Being new to boat motors I am not sure if I am on the right track. Please let me know if I am or any suggestions. Also I am curious how do you tell which points/coils go to which cylinder, so I can make sure that is correct.

p.s. I have done a spark gap test and each plug does have spark.

 

[SparkieBoat]

Re: Johnson Outboard Won't Start

I just refuse to put any $$$ or time into those old motors. There are some other guys in here that love them. My advice would be to buy a good used 1980 or newer motor. but it sounds like maybe you have a timing issue, if it were a newer motor I would say to check the flywheel key. but I am willingly ignorant of those old points motors. sorry I could not help more..but I am sure someone will chime in soon. good luck.

 

[boobie]

Re: Johnson Outboard Won't Start

Do you have the spark plug wires crossed ??

 

[wutevvvver]

Re: Johnson Outboard Won't Start

Do you have the spark plug wires crossed ??

Very easy to do my neighbor completely rebuilt a 1960 evinrude 10hp and did the exact same thing. Right down to the pop.

 

[rgballard]

Re: Johnson Outboard Won't Start

Do you have the spark plug wires crossed ??

I thought the same thing, that is why I was curious to know how to tell which wire should go to top cylinder and which one to bottom cylinder.

 

[SparkieBoat]

Re: Johnson Outboard Won't Start

just swapem and see if it cranks.....

 

[lindy46]

Re: Johnson Outboard Won't Start

Top plug wire goes to the front coil.

 

[nwcove]

Re: Johnson Outboard Won't Start

......havent read anything in this thread about compression numbers?????

 

[nwcove]

Re: Johnson Outboard Won't Start

I just refuse to put any $$$ or time into those old motors. There are some other guys in here that love them. My advice would be to buy a good used 1980 or newer motor. but it sounds like maybe you have a timing issue, if it were a newer motor I would say to check the flywheel key. but I am willingly ignorant of those old points motors. sorry I could not help more..but I am sure someone will chime in soon. good luck.

sparkie!!! shame on you! those oldish motors are perfectly fine, and have passed the test of time.

 

[HighTrim]

Re: Johnson Outboard Won't Start

Dont put money into old motors? You been talkin to my wife? lol Thats just blasphemous.

There is nothing wrong with 50s vintage OMCS. They run strong, are easy to maintain yourself, and are stylish. They do not make them like they used to. I have many motors as early as 1914 still running. Lets see if these modern motors will be running in another 100 years or not.

Sorry to get sidetracked there. What is your initial carb needle settings? As stated, what is the compression? That motor will be in the 100-140 psi range. If compression is fine, and you are getting the spark to jump a 1/4" gap on an inline tester on both cylinders, try spraying pre mixed fuel into cylinders and see if it temporarily fires.

Is this a tiller motor or remote? That mercury switch has to be perfectly level at the start position.

Let us know what you find.

 

[rgballard]

Re: Johnson Outboard Won't Start

Compression on both cylinders is about 110 psi and I definitely get a spark on 1/4" gap. The top carb knob I seated and opened 1.5 turns and the bottom I seated and opened one turn. It is a remote (no tiller handle). Where would the mercury switch be located? This is the first time I have heard this mentioned.

 

[HighTrim]

Re: Johnson Outboard Won't Start

Follow the black lead where it exits the lower cowl. The lead runs to the mercury switch. It looks like a little pill.

I have the same motor on one of the test stands in the basement, I can take a pic.

What is your starting procedure?

 

[SparkieBoat]

Re: Johnson Outboard Won't Start

I knew I could stir up a the old motor guys with that comment.....you will never get me to go back to points..never I say. you will have to peel the power pack out of my cold dead hands....LOL.

 

[rgballard]

Re: Johnson Outboard Won't Start

I don't exactly have a starting procedure. I do it the same as with my 1956 18 hp evinrude. I prime the gas tank and I give it a pull and if it doesn't start I choke it then give it another pull (the evinrude starts everytime).

 

[HighTrim]

Re: Johnson Outboard Won't Start

Try holding the throttle control knob on the start position, ensuring the mercury switch is horizontal

 

[rgballard]

Re: Johnson Outboard Won't Start

Just got home from work and swapped the spark plug wires gave it a crank and it rolled over but didn't start. Gave it two more cranks and bam started right up! This is the first time I have ever heard this motor run and boy I have never been so excited to hear a motor start! Not only did she start, but she stayed running until I turned her off. Since it is 1 am I will have to wait till I get out of work tomorrow to play around with her more.

Quick questions does anyone know what the optimal temperature for a motor like this is to run at? (i.e. most cars optimal running temp is 200 degrees farenhiet) just curious. The motor feels very warm to the touch, but I was going to put the thermometer on it tomorrow and see what the actual temp was. I have replaced the impeller and after watching it run it is pumping water.

Thank you to everyone for your input/suggestions. I can't wait to get this on the boat and try it out!

 

[eavega]

Re: Johnson Outboard Won't Start

Don't know about that motor in particular, but all the outboards I have worked on should have the thermostats that keep the motor temperature below 160 degrees. I think they open at about 130 degrees or so? The actual test in the manual uses "melt sticks" to make sure motor temp gets above 125, but below 163. There should be a number stamped on the thermostat itself indicating the temperature its supposed to open up at.

Rgds

 

[eavega]

Re: Johnson Outboard Won't Start

Don't know about that motor in particular, but all the outboards I have worked on should have the thermostats that keep the motor temperature Between 130 degrees and 150 degrees. I think they open at about 143 degrees or so? The actual test in the manual uses "melt sticks" to make sure motor temp gets above 125, but below 163. There should be a number stamped on the thermostat itself indicating the temperature its supposed to open up at.

Rgds

 

[chiefcatchemall]

Re: Johnson Outboard Won't Start

Not familiar at all with your motor, but I had the same exact problem happening to my 73 20 hp johnson. If you have fuel, compression, and spark in theory it should want to run. It does sound like timing problem to me but that wasnt the case in my situation. My slow speed needle bearing (little plastic cup that sits on the end of the needle) was all chewed up and sitting in the back of the passage. I had to fish it out and install a new one. Ever since then, its been running fine. I could be completely wrong but Im just telling you what happened in my instance.

 

[kfa4303]

Re: Johnson Outboard Won't Start

Glad you got her running. Now would be a good time to mark the upper (#1) spark plug wire so it doesn't happen again. They came with a small metal clip on them from the factory, but a piece of tape would work just as well. The t-stat opens at 140 F, I believe. My exhaust water comes out about the same temp as hot cup of tea. Here's a vid of a motor similar to yours running in a test tank to give you an idea of what to expect.

http://www.youtube.com/watch?v=i6E7P_Hjyps

http://www.youtube.com/watch?v=8vbW12bIQ5k