Johnson 140 not sparking in 1 cylinder

[Revver]

Hi, I have a 1980 johnson 140hp outboard. It will run idle ok but when in water if I apply throttle to move, the engine will die out. I have noticed from taking out the plugs and checking them against the housing, that one of them is producing no spark. I've ruled out a faulty plug by swapping them around and the fault is still in the same cylinder. Before I start more extensive trouble shooting, is there anything I should be looking out for that may cause this?
I am assuming that the motor dying out is related to the spark problem.

 

[HighTrim]

Re: Johnson 140 not sparking in 1 cylinder

Welcome to iboats.

Try a more accurate way to check the spark. Get yourself an inline adjustable tester, available at most auto parts stores, set the gap to 7/16". The spark should jump this with a bright blue ZAP!! If in fact you have no spark on one cylinder, I would first try swapping the coil with a known good cylinder and see if the problem follows. If it does, easy fix, get a new coil.
Good luck, let us know what you find.

 

[tashasdaddy]

Re: Johnson 140 not sparking in 1 cylinder

a high trim said, it could be a power pack failing, you have 2.

 

[big dreamer racing]

Re: Johnson 140 not sparking in 1 cylinder

My 1977 140 HAD the same problem no spark #3 cyl. checked wiring & primary resistance ok no spark swapped coils like they said , then replaced it with a new one. The only issue I had with a new coil Sierra 18-5194 Coil was the spark plug end had a "stupid designed" coiled spring that pierced the wire so I replaced it with an end from a car plug wire & crimped it.

 

[R.Johnson]

Re: Johnson 140 not sparking in 1 cylinder

big dreamer: They have been using that stupid spring for over 50 years with no problems.

 

[Revver]

Re: Johnson 140 not sparking in 1 cylinder

Thanks guys. I know now I've come to the right place for advice. I'll keep you posted...

 

[reelfishin]

Re: Johnson 140 not sparking in 1 cylinder

That spring works fine till it rusts away and falls off. I just got done swapping out all four on my 1977 135 after finding one loose. I didn't have any new spring style clips at hand so I too used a set of automotive type ends and new boots. I had to cut back the wires a bit so using the automotive type ends saved the wires which are attached to the coils on this model. (I assumed that they were only available with the coils since they appear to be glues or epoxied to the coil)?

My later V4s all have removable plug wires for which I've often made my own wires for using good grade boots and solid core wire.