Ignition problem

[Winkster 12]

Hi folks.  I've questioned before and you always answer quick and flawlessly.  Thanks in advance.

 

1977 C-120. 12 HP Kohler. For years I thought it was a 76 (I'm not that bright)

Anyhow, started backfiring and then quit.  Spark plug looked ridiculously carboned up.

I half-assed cleaned the plug. It wouldn't fire with new gas.  What is the best plug to get?  Should I change the coil?  It's pretty old. 

Change the coil wire? Proper settings on the carb?

Ir doesn't look great but generally runs fantastic.

 

Winkster

[953 nut 59,234]

Your condenser or the ignition points could be the problem. Disconnect the lead going from the condenser to the points/coil and see if the problem goes away.The engine will operate without a condenser for testing purposes. Slide a dollar bill between the closed contacts of your points to remove any oxidation there may be on the points/

The Kohler 230722 Condenser fits all battery ignition single cylinder and twin cylinder from the K-90 to the K-582.  The 235786 condensers are for the magneto equipped Kohler engines only K-161 to K-301

The unit of measure for a condenser is the Farad. Many electronic components like radios and TVs use capacitors that are in the microfarad range (ten to the minus six power Farads) and our small engines use a condenser that is in the nanofarad range (ten to the minus ninth power Farads) which is based on the voltage range they work in. A magneto ignition system uses a 100 to 250 nF condenser and a battery ignition system uses a 200 to 500 nF condenser. A good multi-meter will have a capacitor testing function.

Armed with this information you can walk into your auto parts store and get a very confused look on the face of the person on the other side of the counter. The capacitance is not listed on the package and probably not in any of the on-line data they have for the condensers they stock. You just have to go by the application chart and be sure that the condenser you are buying is for the type ignition system your engine has, not just the horsepower or engine size.

If an engine idles well, but runs erratically when revved up, like it hits and misses, pops and backfires, then chances are, it needs a new condenser/capacitor. And always install a condenser/capacitor with the wire facing downward so rain water and/or when washing off engine, water will not enter inside condenser/capacitor, ruining it. With water inside the condenser, this will also allow it to idle well, but cause it to run erratically when revved up.

What is a farad (F)? A farad (F) is the standard unit of capacitance (C) in the International System of Units (SI). It indicates the ability of a substance to hold an electric charge. The value of most electrical capacitors is expressed in farads, microfarads (µF) or nanofarads (nF)