Johnson 6: No spark on both cylinders

[speedlinerbu]

I test ran by Johnson six in a barrel about 6 weeks ago. Last week I strapped it on the roof of my car.
Drove 1200 miles to upstate NY and put it on a Feathercraft.
Will not start. Plugs show signs of fuel.
No spark.
What’s wrong anybody?

[fleetwin]

Can we start with the year/hp/model number of your Johnson 6hp?

[Mumbles]

The list of things wrong could be endless. You didn’t mention what year the motor is but some of the ones from the late seventies with CD ignition had a kill button on them which could be shorted out. That would cause a no spark situation on both cylinders. If it has the CD style ignition, all ground connections must be clean and tight. They are very sensitive to poor grounds. If all of the wiring is good, the power pack itself may be going bad.

Other things to consider on motors with points style ignition would be the condition of the coils. If they are original, they are probably cracked and need replacing. The points, condensers, plug wires, terminals inside the plug boot and the plugs themselves are also suspect. If your motor has points ignition, NGK B6S are a good all around plug to use.

[speedlinerbu]

It’s a 1965 CD 22M with points.
It was running 6 weeks ago.
No cracked coils.
No bad wires.
No kill switch.
A little crud on points which I cleaned off with business card and emery stick.
What I can’t figure out is what changed in 6 weeks and 1200 miles.
And why both sides of magneto at same time.

[frankr]

Do the points again.

[The Boat House]

• This reply was modified 4 years, 10 months ago by The Boat House.
• This reply was modified 4 years, 10 months ago by The Boat House.
• This reply was modified 3 years, 2 months ago by The Boat House.

[outbdnut2]

You mentioned fuel on the plugs. Did you assume there was no spark? or did you clean up the plugs and check for spark in the plug gap with them removed and touching metal,or checked for spark by some other means? The trip could have caused residual fuel in the crankcase to work it’s way through open ports or past the rings to the plugs, and a plug wet with fuel will not spark, as the spark current finds a conductive path from the electrode tip , down the tip’s insulator to the base metal. This is more likely to happen if it was stored or rode with the spark plugs pointing toward the ground , so gravity moved fuel to the lowest point in the cylinder, being the spark plugs. If you did not run the gas out of the carb before traveling, and the motor was on top of the car with spark plugs down, the carb could have emptied into the crankcase with road vibration making this more likely.
Dave

[Mumbles]

Emery will leave a rough surface on the points. They should probably be removed and polished with progressively finer grits of wet n dry paper or replaced. 1000 or 1500 grit will leave a nice shiny surface on them and a wash in lacquer thinner or something similar will remove any oil film left behind. They have to be clean to work properly.

• This reply was modified 4 years, 10 months ago by Mumbles.
• This reply was modified 4 years, 10 months ago by Mumbles.

[fleetwin]

OK, well does it spark now after you cleaned the points? If not, seems like something happened on the roof rack during the drive to upstate NY. Let us know where you are at now…I am assuming that valuable vacation days are wasting away without the outboard….

[amuller]

Sometimes points seem to insulate themselves with crud very quickly, for no very obvious reason. Travel equipped as if you expect to have to service the motor….. Take motor old enough to have the window in the flywheel for cleaning the points.

[Author]

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