Johnson 40hp won't start

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blacktrain

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Older Johnson 40hp, Has 180lb compression each cylinder, has two new plugs, fresh fuel, and has super good spark. Will not start, pulled the plugs, squirted fuel into each cylinder, reinstalled plugs, won't even fire, nothing at all. I appreciate your help. Thanks...
 
oldboat1

oldboat1

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might be a '94, but model number shown may be incorrect.

Get an adjustable spark tester and measure spark -- should see something around 1/2 inch, and bright.
 
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blacktrain

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I tried a spark test with my #20610 Mac spark tester and the spark is 1/2" or more and is a very hot blue spark. The spark is large. You can hear it snap. I appreciate your help. Thanks...
 
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racerone

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With a bit of fuel in the cylinders you should at least hear a pop.---------Orange / blue stripe going to the top coil ?----When did it run nicely for you ? ----What happened ?
 
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blacktrain

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When I serviced it last fall it ran great. I disconnected the fuel line from the carburetor and run the engine to burn up the fuel in the float bowls, when the engine started to sputter because it was running out of fuel, i started to spray fogging oil directly into the air intake so it would coat the inside of the carbs. as well as the cylinder walls. I do this every year. Then this spring I filled up my fuel tank with hi-test fuel and before i hooked the fuel back up I cleared the fuel line by holding a phillips screw driver into the end of the fuel line and squeezed the primer bulb until nice fresh fuel flowed. Then i hooked up the fuel line to the motor. I squeezed the primer bulb until hard. I cranked the engine over, choked it, nothing happened. After several attempts I pulled the plugs to see if they were wet. They were soaked with fuel. I turned the engine over with the plugs out and a lot of fuel came out of the plug holes. I turned the engine over several times to clear the cylinders. Once cleared, I put in a fresh set of plugs and tried again. The engine doesen't even putt. I sincerely appreciate all your help, Thank you...
 
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racerone

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Motor needs to spin over FAST ( with plugs in ) or the ignition does not produce spark !----Test starter / load test battery / inspect cables.
 
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blacktrain

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With the plugs in the motor spins just like a new one. The battery tests 13.36 volts ,load test on the tester that i have reads 10 on the green scale. My tester has a red, yellow, and green scale. Tomorrow I will find out the voltage draw of the starter, it turns over to beat the band, but i will test it anyway and i will let you know. Again I sincerely appreciate all of your help...
 
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blacktrain

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One of the first things i did was test for water, that's one of the reasons i clear the fuel line first before i connect it to the motor. Thanks for everything and i will be in touch tomorrow.
 
oldboat1

oldboat1

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probably QL78C Champion plugs -- believe the gap would be .030. Possibly an incorrect plug or gapped too wide?
 
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blacktrain

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The starter draw is around 100 amps, The plugs are QL78C and they are gaped at .030. update: I tried to start the motor this morning and it tried to start. Would run for 2-3 seconds and quit. I tried it several times and sometimes it would fire for a second or two and other times you could crank it and nothing. I tried squirting fuel into the carbs when it tried to fire but made no difference. I pulled the plugs and they are wet but not flooded. Even though I seem to have good spark maybe its not enough? If all else fails I am willing to bite the bullet and buy whatever i need to improve the spark. What would I need to purchase if I choose to do this Stator, Timing base, coils, etc. I don't have any idea what I would need. Thank you all for your help you all are greatly appreciated...
 
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blacktrain

Seaman
Joined
Jul 20, 2013
Messages
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The starter draw is around 100 amps, The plugs are QL78C and they are gaped at .030. update: I tried to start the motor this morning and it tried to start. Would run for 2-3 seconds and quit. I tried it several times and sometimes it would fire for a second or two and other times you could crank it and nothing. I tried squirting fuel into the carbs when it tried to fire but made no difference. I pulled the plugs and they are wet but not flooded. Even though I seem to have good spark maybe its not enough? If all else fails I am willing to bite the bullet and buy whatever i need to improve the spark. What would I need to purchase if I choose to do this Stator, Timing base, coils, etc. I don't have any idea what I would need. Thank you all for your help you all are greatly appreciated...
 
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racerone

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Do this test-----With the plugs in the motor do you have spark that will jump a gap of 7/16" ,----yes or no ?
 
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