mtd key switch 725-0267 or 725-1396

[38racing]

The ipl for my mtd mower shows mostly the 0267. That is the number on my ipl on my style number (8), But later in a wiring diagram (one of several) it shows my engine (15.5) with the 1396 . Yet on another it shows the 0267 for the 15.5. On my unit it has usual 5 terminals for the plug connector plus an extra terminal with a red wire on it. looking up switches I see the 1396 has that extra terminal and the pin locations are not the same on the two switches. I have a 0267 on hand but looks like I have to get the 1396 or switch wires around (asking for trouble in the future for someone). So to double check it's back to the VOM. Any guidance on the extra terminal and it's red wire. Those ipl wirings show next to nothing. Also it is a 678 model, 2003 I think. No RMC module ,as I found in newer units that extra terminal is A2 and may be used for that.

[38racing]

What i found so far. the 5 pin 0267 connects b-L in run only. not start. i remember having that issue in my 85 yardman tractor when i was upgrading to have a seat safety. it means 0267 has no support for antifire solenoid. now on the 1396 i found the usual connections but b-L is in both run and start so L can be used for antifire solenoid. i found that 6th pin is connected to the g and m in the off. in run it is connected with the b and L. in start it is not connected to any other pin.now have to trace that wire on pin 6 in the morning. my problem is intermittent loss of voltage to the antifire. touching switch connector will drop it. in switch check seems like b-L drops on key jiggle or on unit plug connector jiggle.

[KE4AVB]

Not the best images for the 725-1396 setup but should help but looks like you already got it mapped out..


On the diagram I have>
L goes the carb solenoid
A goes to the regulator
B goes to battery
S goes to starter system
G goes ground
M goes to magneto

[38racing]

Since i do not have regulator A wire is probably from the stator. i can check that easy.

[KE4AVB]

Could be use for lighting too in the run position. The regulator note is from one of the MTD wiring diagrams using this switch. I wouldn't be grounding the stator as it could destroy it as that would be direct short to ground.

[38racing]

Have not checked that wire yet. i put the switch back on and replaced antifire with a bowl nut so i could get the grass cut.
If it were stator feed it would put 12v to magneto when key went and engine continued rotating.

[wristpin]

The most important thing when substituting switches is to ensure that you don't send a dose of volts down the ignition coil kill wire, if you do it will kill the coil - permanently! To be safe, disconnect the kill wire at the coil end while experimenting and connect it to a an earthed low wattage bulb or multi meter. If it lights at any key position you have got it wrong! I've actually got a little buzzer which saves having to watch a bulb or meter.

[38racing]

The most important thing when substituting switches is to ensure that you don't send a dose of volts down the ignition coil kill wire, if you do it will kill the coil - permanently! To be safe, disconnect the kill wire at the coil end while experimenting and connect it to a an earthed low wattage bulb or multi meter. If it lights at any key position you have got it wrong! I've actually got a little buzzer which saves having to watch a bulb or meter.

The way it is with cellphones now I expect there are hundreds of tones to download to replace that buzz.lol .