[Rick81]

As strange as the title sounds, that's the situation I have. I replaced the carb based on the age and symptoms I was having with no change. Also threw in a new plug since it was original with no change. Finally I put the inline spark tester on hoping to verify the coil was the problem and low and behold it fired right up. Ran it for 15-20 minutes like this with no cutting out. Removed the tester and put the plug wire back on the plug and I am back to a no start condition. I get a momentary fire with each pull but it never completely starts.

If I put the tester back inline it starts on the first pull every time. Has anyone seen this happen before? Is the coil wire the problem or not making good contact with the top of the plug? If that's the case I guess I need a new coil since the wire and coil appear to come as one piece.

Thanks!

 

[wwxx]

I don't know what a husky 125 L is, is it a chain saw, trimmer, motorcycle, or riding mower?

No, you don't have to buy a new coil, necessarily. Those things get kina expensive.

You might make sure it is just the high tension lead that is the problem (which it sounds like, it is)...sometimes you can spray the lead with water or WD-40 until it shows 'no spark at all on your tester', or quits missing...as the case may be. Sometimes it helps alot to inspect the coil wire, as the engine is running, while it is dark outside. A leaking high tension lead with show a spark, not unlike your inline tester shows.

Often you can try simply wrapping the high tension lead with a neat, tightly wrapped plain old electrical tape. Oft times on chainsaws & the like, the high tension lead might be sealed with a simple coat of 'silicon glue', especially at areas that contact metal.

But to seriously repair a coil high tension wire, most magnetos, that appear to have the high tension lead 'glued into the coil', can sometimes still be repaired, instead of replaced.

I cannot say for sure this will work on your magneto specifically, but usually I simply grab with pliers the high tension lead close to the 'sealed connection to the coil'. Twist and pull, attempting to 'crack the sealer glue' enough so that you can unscrew, or probably more like Dig the wire out of the coil. Most magneto type coils, have a sheet metal stud imbedded within them, that the high tension lead screws onto, the factory adds a bit of sealer/glue to hold it in place permanently. Now the only trick is to find a replacement piece of high tension lead (of same diameter, & metal core) and screw/glue it in place. And ya just saved yourself $45 bucks.

wwxx

 

[Rick81]

I don't know what a husky 125 L is, is it a chain saw, trimmer, motorcycle, or riding mower?

No, you don't have to buy a new coil, necessarily. Those things get kina expensive.

You might make sure it is just the high tension lead that is the problem (which it sounds like, it is)...sometimes you can spray the lead with water or WD-40 until it shows 'no spark at all on your tester', or quits missing...as the case may be. Sometimes it helps alot to inspect the coil wire, as the engine is running, while it is dark outside. A leaking high tension lead with show a spark, not unlike your inline tester shows.

Often you can try simply wrapping the high tension lead with a neat, tightly wrapped plain old electrical tape. Oft times on chainsaws & the like, the high tension lead might be sealed with a simple coat of 'silicon glue', especially at areas that contact metal.

But to seriously repair a coil high tension wire, most magnetos, that appear to have the high tension lead 'glued into the coil', can sometimes still be repaired, instead of replaced.

I cannot say for sure this will work on your magneto specifically, but usually I simply grab with pliers the high tension lead close to the 'sealed connection to the coil'. Twist and pull, attempting to 'crack the sealer glue' enough so that you can unscrew, or probably more like Dig the wire out of the coil. Most magneto type coils, have a sheet metal stud imbedded within them, that the high tension lead screws onto, the factory adds a bit of sealer/glue to hold it in place permanently. Now the only trick is to find a replacement piece of high tension lead (of same diameter, & metal core) and screw/glue it in place. And ya just saved yourself $45 bucks.

wwxx

Thanks wwxx- I will give that a try tomorrow. I'll let you guys know what happens.

Oh and it's a trimmer from around 2008.

 

[Obscured_by_Clouds]

Is the coil wire the problem or not making good contact with the top of the plug? If that's the case I guess I need a new coil since the wire and coil appear to come as one piece.

First thing I'd try is using needle nose pliers to squeeze the contact in the end of the wire that fits on the plug to make sure it seats tight.

 

[Tom-machinery-idiot]

This goes back forty years. A guy I was stationed with in the Air Force had a Fiat X19. He bought a gadget which was touted to increase, or amplify the spark. He got curious so he took it apart to examine it. Little round plastic cylinder with a wire coming in, a wire going out. He was supposed to connect it between the coil and distributor. When he got it apart, he found it consisted of two rods, one connected to each wire. The rods were sharpened like pencils and the points were positioned 3/16" or so apart. It was just a gap, exactly like a spark tester.
He got curious and asked around. An old auto mechanic told him that a gap in the wire like that would actually increase the spark. Make it hotter. I have no idea how that works but your story reminded me of that. Sounds like the same situation.

 

[markusedma]

I have also witnessed this same thing. I ended up replacing the coil. I don't recall what principal comes into play with an added gap, but yes it can boost spark strength. Likely you just have a weak coil. You can try removing the coil and baking it at LOW heat in an oven and see if that helps, but as I said.... Likely need a new coil. Make sure that the kill wire is not grounding or "leaking" to ground first by disconnecting from the coil if you can. And one last thing to check is that the flywheel key is not partially sheared...if timing is advanced the tester could be providing just enough delay..

 

[tomw0]

You raise the voltage by increasing the gap, or adding a second, larger gap in series. The spark can jump a small gap at lower voltage than required to jump a larger gap.
The 'intensifier' just added more gap so that the voltage from the coil had to climb a bit higher before it could jump, and when it did, the jump on the plug, a bit further down the road from the coil, had to increase also. I am guessing that the higher voltage spark enabled the engine to fire...

If you just opened the plug gap, you would do the same thing as the spark tester. Your coil must be functional to be able to jump the tester and the plug.
Solution to me would be wider gap or new plug.
tom

 

[Tractor-Holic]

I had one of those "spark intensifiers" on my '56 Chevy pickup--former owner must have installed it--I think it was an Accel brand...it plugged into the coil wire socket on the distributor cap,and the coil wire plugged into the "intensifier"...

I could feel a difference in the way the truck ran with it,vs without...the distributor cap had a habit of getting all carboned up inside the coil wire socket and needed replacing every so often--once it stalled on me and refused to start,until my dad pulled out the coil wire and used a pencil eraser to shine up the sockets brass insert..

As Tom stated,the "intensifier" is really just an air gap inside a sealed chamber--I read in my old 1941 Audel's motor manual that an air gap does tend to increase the spark's intensity because it allows the coil to build up a higher charge before its magnetic field collapses when the points opened,to fire the plug--and if the plug was fouled ,the spark would tend to jump both the air gap and at the plug's electrodes at the same time,rather than the spark taking the easiest path to ground through the fouled spark plug,and causing a misfire..

Personally if it were my tractor I'd just try running it with a longer boot on the plug wire,so the spark has to jump about 3/16" ,rather than have it connected right to the plug...maybe the plug is a resistor plug and the coil cant fire it without the air gap?...this is one of those strange things that often happens on engines that no one seems to know why it works that way--it just DOES!...:dunno:

 

[rayjay]

I used this trick many times to get a trail bike with a fouled plug back to the shop.

 

[wwxx]

I guess the cheapest solution is to leave your in-line spark tester on there & run it like that indefinitely. (something I would probably do, I don't weedeat much) haha

With conversation of spark intensifiers...makes me think, perhaps your spark plug was replaced at some point, with a non-resistor type spark plug?? A new spark plug, of the resistor type, might fix the problem.

You might check your original warranty papers, some manuf. offered an extended warranty period on the usually very reliable 'electronic ign. magneto', even tho yours is around 7 yrs old now, it might still be warrant-able.

wwxx