old johnson coils, can they look good but be bad?

[ronboonville]

I tested the resistance on the coils awhile back and they checked good. but still lower cylinder had no fire. swapped coils from one side to other and still had no spark on lower cylinder. installed new points and cond. and everything was good. ran good in barrel. started yesterday and sounded like it was running on 1 cylinder. took it to the water anyway thinking it would get better, not. would not engage reverse so I beached the boat and looked at linkage, bracket was loose, then fell into lake. okay, no problem, had old trolling motor and battery for back-up. headed for ramp now and halfway across small lake noticed I was taking on water! lots of water! made it though with about 2 inches of water line at back of boat. Oh and bilge pump had come apart. Are we having fun yet? drained about a jillion gallons out. found problem with bilge pump and found the live well drain hose was broken. Okay water problem solved. so, back to my question can coils look good and test good be bad? can heat affect them? only 106 degrees here. engine was cool enough to put hand on flywheel. this is a 1960 gale 35hp. similar to a lark or big twin. will pull flywheel and check points today but was thinking about buying new coils, hate to because of cost. but havin fun ain't cheap. any feedback appreciated, thanks, ron

 

[fireman57]

Re: old johnson coils, can they look good but be bad?

yes they can be bad and look good just like women. If you swapped them though and still had no spark with a known good coil then it probably ain't your coil that is bad. They can overheat when running and short out but look fine. Usually though you will see a hairline crack in them or the plug wire will loosen in them especially on the new coils that you have to put together yourself. Sounds like some of my fishing trips, everything seems to happen at once. Good reason for a spot check of everything before you leave the driveway.

 

[Chinewalker]

Re: old johnson coils, can they look good but be bad?

How are the plug wires? Old wires can crack and arc out to the block or stator plate.

Do you have the points oiler wick in place? Is it lightly oiled? Points riding dry on the cam can close up as the rider wears down.

The points are new - are they clean? SPOTLESS clean? Handling with greasy hands when installing can cause intermittent spark.

 

[ronboonville]

Re: old johnson coils, can they look good but be bad?

okay, noticed flywheel was dragging a little, cleaned and reset points, they had gone to about.018, pushed plug wire in as much as I could without taking plate off, backed the mags off a little less than flush, replaced fouled plug with best used one I had, put back together, fired right up, in barrel, leaned out high speed, then it died, forgot to hook up fuel line. I still don't know where the oiler wick goes so I put a little grease on cam. if lower cylinder keeps fouling could there be a passage plugged up some where? will take extra plugs like I have to for my old motorcycle thats a couple of years older. rings maybe? any thoughts?

 

[fireman57]

Re: old johnson coils, can they look good but be bad?

Don't use anything except the correct champion plug in these engines. They were literally designed around these plugs

 

[nwcove]

Re: old johnson coils, can they look good but be bad?

also, pushing the wires into the coils is not a good plan, they screw in.

 

[ronboonville]

Re: old johnson coils, can they look good but be bad?

yeah I know they screw in. but didn't want twist around anymore. and wanted to make sure boot on all the way. anyway running good now. thanks, ron