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Johnson 150 GT troubles

D

drawers

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I recently bought my first Johnson motor, so far I feel like it was a mistake. The guy I bought from said he had only owned it for a couple weeks and didn't have time for another project. He said he put it in the water and it ran for a few minutes at WOT and then played out. Sounded like a carb job and cleaning of the fuel system and I would be good to go. I have rebuilt carbs, fuel pumps, new fuel lines and vacuum lines, new gas. I have read and become familiar with the starting procedures recommended by others and this is what I get. It starts and runs for about thirty seconds, dies and won't crank again for twenty or thirty minutes. I'm tapped out. Frustrated. Thinking about starting a big fire!! Any suggestions, and not about starting the fire, I can handle that. Thanks
 
Have you checked the compression on it?? Will the spark jump a 7/16 " open air gap on a spark tester when it quits ??
 
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I have checked the compression and it is 85 +/- on each cylinder. I checked the spark and now I have none. I had to have some fire for it to crank at all. Now I have no fire at all on any of the cylinders. The stator looks like it has been replaced recently with a CDI brand. Could it be in the ignition switch or the kill switch and how do you test these? What else could cause no fire at all? Thanks Boobie
 
Boobie said:
Find the black/yellow wires going to the power packs, disconnect them and see what happens.
Click to expand...
I bought a spark tester this morning and checked for a 7/16 spark but had none on all six. Disconnected the black/yellow wire and no change, turns over but doesn't fire. I put a test light in wires from stator plate to power packs on both sides and it lights up. Blue wire from rectifier that is attached to bottom screw on wiring bar is somewhat melted at screw. All other wires look normal for age of motor. What's next?
 
You will need a DVA and a DVO Meter when checking this system not a test light.



DVA Explained DVA stands for Direct Voltage Adapter, which is used to measure peak AC voltage. This type of

measurement of AC voltage takes the absolute peak or highest value of the fluctuating AC

voltage signal. Peak readings will be substantially higher than standard or RMS AC values and

are typically used when testing marine CD (capacitor discharge) ignition systems due to their

high variance in frequency as RPM increases and decreases.
 
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