MF12 Key switch

Hi everyone; I have a 1968 massey furgensom MF 12 that im replacing the key switch. on the back there 4 conections, one has an s for start, B for battery, then there is one that has a D, and one that has a c. Does anyone know what these are for?
the old switch fell a part. the new has B, S. IGN, AND ASSC. I NEED TO KNOW WERE TO put THE C AND D WIRES.

THANKS HOWARD

Does your tractor have a coil mounted on or near the engine, or does the spark plug wire come out of the engine shroud? If it comes out of the shroud, I think you have the wrong switch. The electronic ignition will get fried if you put 12 volts to the wire that needs grounded to shut off the engine.

I think the correct switch would have a G terminal.

When replaceing ign sw on this mod/yr tractor you must be extremely carefull as to connections on ign sw & type of sw needed,you're going to have to do some exploreing/detective work on eng/tractor frame,if eng a tecumseh HH120,in late 60's eng used either a starter/generator or a ring gear on flywheel & gear type starter,most of these ign sw's of this time frame were hd & designed to carry full current from battery to s/g or starter motor,most/all standard/univ ign sw's today are designed to be used with a starter sol & will only carry s/g or starter load thru contacts for a short time,then burn out,you'll have to add a starter sol to s/g or starter motor,the biggest problem is ign system,in that era tecumseh used 3-4 different ign systems depending on starting system,if s/g ign could be points/mag,12v points/coil or early solid state system mounted under flywheel,if standard starter(gear type)ign could be 12v point/coil ign or solid state with a large cast alum ign module mounted on block over flywheel & powered by a seperate winding on alt stator or possibly under flywheel type,12v points/coil ign needs a battery ign sw,points/mag coil & either type solid state system require a grounding type sw(magneto)as steve stated sw may have a G term on it or grounded internal thru shell of sw,you have to check with an ohmmeter/powered test lite to determine if new sw grounding sw or 12v ign sw,as steve also stated,if you have wrong sw you will you WILL burn out mag/solid state system by appling 12v to either,1st you'll have to determine type of ign system on eng & if sw right type,in addtion to possibly adding starter sol,you might also try local simplicity dealer,in that time frame most simplicity,mf & allis tractors were built by same mfg,take mod/sn #'s with you,he may be able to cross ref & oem sw may still be avail.

My MF12 has the new stile ford like selinoid that mounts on the back of the engine and it front of the voltage regulater. Were can i find a ign sw that is the right one?

THANKS HOWARD

Most any single term coil connection sol will work with a 12v ign or grounding type ign sw,your problem is to id the type of ign system on eng & get correct type of ign sw for ign system on eng.You can't get correct ign sw if you don't know which ign system on eng,also as I said in 1st reply,try a simplicity dealer,I used to get parts for my 73 mf8 at simplicity dealer.What make & mod eng on tractor?

In your last reply you mentioned a regulator,if this is a blk box with 3-4 terminals on it & mounted on a generator and either/both have delco marked on them,and a belt between generator & a pulley on flywheel you have a starter/generator,in which case eng ign could be 12v point/coil or mag/solid state,if eng has an auto style coil mounted on flywheel cover and a box/cover to right & slightly below carb with 1 or 2 wires going into same ign system 12v and you need a 12v ignition sw(ign sw must provide 12v to coil when cranking/running)IF plug lead goes into flywheel cover,then you have mag/under flywheel solid state system,in which case you need a grounding type ign sw(when sw in off/stop position 1 of the term on sw will read with ohmmeter/test light to sw shell or G term on sw)as far as D & C wires you'll have to trace them,one of the wires will goto ign coil(12v) or into flywheel cover(mag/ss ign),other wire probably for acc(lights,cig lighter,electric clutch or any other 12v accessories on tractor)IF YOU DON'T HAVE elect knowledge/tools to work on elect system/ign sw,take tractor to local mower shop & have them get/install new ign sw,if you install wrong sw/type of sw or connections wrong,1st time you turn on ign sw you may be spending $75+ for new ign system parts