sa 200 sa200 no spark magneto fmx

[92dlxman]

a friend of mine had his welder stop mid-day on him. blackface 200 with continental f163 and of course the fairbanks morse fmx magneto.

we quickly decided it was a no-spark condition by the smell of raw fuel from cranking and the fact that we could get no arc by shoving a screwdriver into a plug wire and bringing the shaft close to "ground" (like a spark plug).

the machine did give some warning as it ran like poo before shutting down. for a few days it would spit and sputter, and i warned my buddy that he either had a serious spark or fuel issue.

anyway, i isolated the kill (grounding) wire from the ignition switch to see if there was a fault in the switch itself to no avail and i also shorted that wire to ground and saw that it makes a pretty nice spark while cranking.

so the mag makes juice, but does not send to the plugs

the cap in my opinion looks like crap, with heavy pitting at the 4 contacts, but i wonder if that would make a machine just completely not fire at all? seems like we would get a lucky hiccup on occasion?

other than that, i cannot verify points gap or even see them without pulling the machine.

so the big question is: does the fact that the kill (ground) wire gets juice mean that the cap/ rotor are suspect for sure? or could it still have something to do with points/ condensor?

[charlie53843]

Sound like need little love!! pretty easy work on, i buy my rebuild kit from Standard magneto ,, but if money tight at moment you clean all metal contact with little sand paper spray with electrical cleaner , file point, check proper gap on point will be .015

[duaneb55]

If you can get to it to get them off, pull the distributor cap and cover and holding a screwdriver against the mag housing with the tip 1/4-3/8" away from the coil tab, crank it over to see if it jumps a good hot spark.

If it does, the coil, points and condenser are good and the distributor cap and/or rotor would be suspect. If cracked, sometimes you can see a carbon track where the spark would travel to ground instead of out the wire(s) to the plug(s). I've also seen the spark travel down the coil and jump to ground due to a compromised coil body.

[Dana gear]

As in Duaneb 55 post above if you have good spark at the magneto coil check the carbon contact for the rotor. I have seen them fail at times as well as corrosion on the high tension lead rod.
Points are more then not the culprit on these, I seen more then I want to admit wear the rub block down on the points slowly decreasing point gap to the point it will not run.
Coils can and do fail but its not that common, also check for excessive play in rotor shaft.

[92dlxman]

thanks guys for the thoughts!

he is pulling the machine this weekend but i wont get to see it till next week. ill keep ya posted on what i find

thanks again!

[mugzy]

I got the carburetor to work, cranked it over, it was running fast and motor quit. Checked out this tread and am going out to ground the coil and see if that is putting out. This continental 163 is starting to wear on my patience. Trying to find out why it lost its spark. M

[smithdoor]

Most time I had that problem the magneto need to be recharged. They need recharge every 30 years may last longer.

Dave

a friend of mine had his welder stop mid-day on him. blackface 200 with continental f163 and of course the fairbanks morse fmx magneto.

we quickly decided it was a no-spark condition by the smell of raw fuel from cranking and the fact that we could get no arc by shoving a screwdriver into a plug wire and bringing the shaft close to "ground" (like a spark plug).

the machine did give some warning as it ran like poo before shutting down. for a few days it would spit and sputter, and i warned my buddy that he either had a serious spark or fuel issue.

anyway, i isolated the kill (grounding) wire from the ignition switch to see if there was a fault in the switch itself to no avail and i also shorted that wire to ground and saw that it makes a pretty nice spark while cranking.

so the mag makes juice, but does not send to the plugs

the cap in my opinion looks like crap, with heavy pitting at the 4 contacts, but i wonder if that would make a machine just completely not fire at all? seems like we would get a lucky hiccup on occasion?

other than that, i cannot verify points gap or even see them without pulling the machine.

so the big question is: does the fact that the kill (ground) wire gets juice mean that the cap/ rotor are suspect for sure? or could it still have something to do with points/ condensor?