6 volt coil

I have a MM ZA that just pops and quits. It started easy and run fine until all of a sudden it sputtered and quit like it was out of gas. Its not out of gas. The flow is fine out of the carburetor port. . Seems to have low spark. Im sure the ignition system has not been touched in over 20 years. Thats how long Ive had it. Bet it could easily be 40 years since it was touched. Im going to buy a spark tester next chance I get to town. One of the things Im checking is the coil. It has 1.2 ohms between + and -. It has 6000 ohms between + and tower. The secondary seem high to me. Im I correct? Any ideas?

Why buy a spark tester when your likely to have what it takes to make one. Simply take an old plug and gap it out to a 1/4 inch gap and use it

Theres a gazillion coils out there and Ive seen or heard or read of HV Secondary resistance in the 5,000 to 10,000 ohms range and your 1.2 Ohms LV primary is in a range Ive seen 6 volts coils have.

HOWEVER its easy for a coil to pass a low energy low voltage ohm meter bench test BUT STILL BREAKDOWN UNDER ACTUAL HIGH VOLTAGE AND TEMP REAL WORLD CONDITIONS (known as High Voltage breakdown) .......An ohm meter can show if a coil is BAD but it cant tell you if its GOOD !!

NOTE the more common cause of failure IS BURNED CARBONED OR PITTED POINTS and sometimes a condensor MUCH MORE COMMON THEN A BAD COIL.......

I would start with as non abrasive as possible clean/buff/polish the points and check their gap, however if badly burned carboned or pitted REPLACE THEM, especially if they are 20 years old !!!!!!!!!!! If needed (typically they dont go bad)it may need a condensor but so often new out of the box are bad or no better then an original

Check points and gap and ALSO a bad cap or rotor (burned/cracked/moisture/carbon traces) or bad spark plug or coil wires can break down. Are they old or brittle or cracked etc???????? How does the cap n rotor look ??? Ive seen rotor tips short out !!!!!!!!!

Sure coils can fail buttttttttt Id check points and gap and cap n rotor and wires FIRST

See if others agree or not ????????????

John T

Thanks John. I agree with everything you mentioned. Just was not sure of the coil resistance. It was easy to get to. The distributer requires more to get to and as old as it is Im afraid to even take the cap off without a replacement cap. The condenser is my first real suspect, then the points. Ill let you all know when i get it fixed..

Youre welcome, you can do this, let us know what you find

John T

That's the bad thing about a MM ZA. You can't get at the distributor without taking the entire hood off. Not one of their better ideas! It does keep it from getting wet, but a pain to work on otherwise. Been a long time since the points on mine have been looked at also.

That is the only reason I started with the coil. It was easy to get to. As a teenager I did most of the tune up work on the farm. But that has been most of 50 years ago. I still have all my mechanic tools but have not done many
tune ups since. So I guess the hood comes off and I go to work.

I don't have a lot

Of confidence using a ohmmeter when testing a coil.

This coil came off my 2007 GMC. An ohmmeter will tell you the coil is good.

Best to replace the coil, points, condenser, rotor and cap.

I am not saying you don't have an electrical issue but I would do further testing of the fuel system before taking off the hood.

You said it starts and runs fine then sputters and quits like it is out of gas.

-Does it fire right back up?
-Do you have to wait a few minutes before it will re start?
-Does it sputter and die consistently or will it sputter and keep running some times?
-Does it die faster if you throttle up right away?
-What is the age and quality of the gas? A little bit of water can cause the same symptoms you described or it could be something as simple as;
-A pinched fuel line
-Plugged filter or screen
-Clogged vent....