Just because the letters match, doesn't mean the switch is wired the same way internally.

Some old switches put 12V to the ignition coil to run.
Newer ones ground the coil to kill.
Old type switch on a new system can "fry" parts.

I have absolutely no idea what switch you need or what you bought.

i tried disconnecting the wire that hooks to the coil and it fires right up but wont shut off. with that being said im assuming that it grounds the coil to short it out and shut her down... the part number off the switch that was given to me is: 925-0267B and the package says mtd genuine parts. the parts guy said it would work. it almost has to be an issue with the new starter switch i dont know..

The part number to the switch is meaningless without having the "truth table" which shows what connections are made/not made in the various switch positions.

The coil wire IS grounded to kill the engine.

It is "typically" connected to the M terminal of the key switch, which is grounded to the G terminal in the OFF position.

Older switches had the "M" (or equivalent) connected to the Battery in the ON position to SUPPLY 12V to the battery/points ignition systems they had.

the original and the new switch both have the letters: S,M,L,G,B. What i do know is the "S" terminal goes down to the starter sol. If i could figure out what the other terminals should be going to i could trace the wiring and figure somthing out maybe that way...

thanks again for all your help!

right now the M terminal has power all the time to it and the G terminal gets power when the key is turned to the run postion. The S terminal gets power to it when you turn the key to crank postion.

go to this site look for switch with the right number of terminals
and positions and it will tell you what goes where
not the same number as you have I could not find that number
but hope this will help u out

Here is a link that might be useful: jackssmallengines

Your switch is obviously wired wrong, or more likely, the wrong switch.

I don't know the MTD layout for all the terminals, but-

B hooks to the battery
S goes to starter solenoid.
G should be GROUNDED.
M goes to kill wire on coil

L might be a light switch
OR
it might go to the carb fuel solenoid
OR
alternator output
OR
????
OR
some combination of the above

ok thanks i will dig into it this weekend and let you know what i find out.

sorry i didnt realise i was posting in lawn mowers forum and lawn tractor forum... i bought a new switch from john deere today and installed it everything is wired its original way. cranks but no start. no spark.... removed ground wiring off coil and it will fire right up.. anyone have an idea??
thank you

Safety switch.
Seat switch seems to be the more common culprit, but attachment/PTO switch is a possibility.

I don't have any DEERE schematics and I'm not willing to pay for them, so I can't really help on any troubleshooting procedure EXCEPT-

Make sure all the switch connectors are clean & tight and the switch is adjusted so that it moves when it should.

Seat
Brake/clutch
Attachment/PTO

Depending on the circuit, sometimes disconnecting a switch insures no spark.

If it's cranking, it's most likely not a safety switch. If a switch was bad it wouldn't even crank. Get an ohmmeter and measure continuity on the wire from the coil to the keyswitch. Makesure it goes to the M position on the switch. With the key in the OFF position you should measure a short between the G and M terminals on the switch.

"If it's cranking, it's most likely not a safety switch. If a switch was bad it wouldn't even crank."

Do you have a schematic that proves this highly unlikely circuit?
I've NEVER seen a seat switch that had anything to do with the crank circuit.
A Brake/Clutch switch can have 1/2 of its' functions bad and crank the engine.
A PTO switch can have 1/2 to 2/3 of its' functions bad and still crank the engine.

"A Brake/Clutch switch can have 1/2 of its' functions bad and crank the engine." This is true. The majority of clutch switches are 4 pole- 2 normally open and 2 normally closed. 2 on the crank circuit and 2 on the shut off circuit w/ the pto and seat switch. With the manual pto, I don't believe they will crank if failed. On these, a likely candidate is that clutch switch or the fact that it isn't quite being actuated enough. A short to ground can also tend to happen back near the starter solenoid. But I THINK that is after the clutch and before the seat switches. Sorry if I missed this, but attention needs also to be paid to the corroded terminals in the switch block. Possibly the clutch switch block as well. It may not be related to this problem- but will come back to haunt you.

"Do you have a schematic that proves this highly unlikely circuit?
I've NEVER seen a seat switch that had anything to do with the crank circuit."

Funny...I never said seat switch. I said A safety switch, which could be the PTO or clutch/brake. I've NEVER seen a safety switch "half fail", since the plunger has one piece that contacts both sides at once. I'm just giving the guy some ideas, Ace. You don't heve to be rude.

smallengineguy - no pass. seat switch definitely belongs in safety switch family....

That's what I meant. It could be ANY of the switches, not just the seat switch like Billy said.

EXACTLY WHERE did I say THAT?

There are only 3 people that I allowed to call me "Billy" and YOU aren't one of them!

I do have an ohm meter! i will check the switch they gave me. im questioning if they even gave me the right switch?? again if i disconnect the grounding wire to the coil the engine starts and runs great! so im assuming that the safety switches are good?? i DONT HAVE A SCHEMATIC of the mower wish i could find one online somwhere for the tractor. i will check the terminals on the switch tonight and get back to you.. how do i test the safety switches exactly? the seat switch i put a jumper wire in and it did nothing.... the clutch switch is a 4 wire switch and there is another one for the deck that is a 4 wire. which i assume keeps the mower from starting if its engauged. not sure how to test the 4 wire switches.. thanks again for the help

bobthemowerman1 - cut to the chase. get ahold of john deere service dept.. spend a few bucks for the service manual and elect schematic. get the machine fixed or take the machine to a qualified shop that can do same.

A seat switch can be wired in so many different ways, there's no way to really tell. (actually you can, IF it's working correctly in the first place, you can see what actions mess things up)
OFTEN, "jumping" OR disconnecting it will insure the engine doesn't have spark.

Brake/clutch & attachment switched are more straight forward.

ON means continuity-
B/C up, kill circuit ON crank circuit OFF
B/C down kill circuit OFF, crank circuit ON.

PTO/attachment switch OFF Crank circuit ON & kill circuit OFF. OPPOSITE for ON.

I wish I had JD schematics also, but they charge for them.
I do have a couple, but not for your machine.
They also may be different from year to year.

"There are only 3 people that I allowed to call me "Billy" and YOU aren't one of them!"

That's funny as hell! Anyway...I know the JD dealers near me will make me a copy of the wiring schematic for no charge. Try this: Unhook the coil wire. Then start it. After that, disconnect the keyswitch with it running, then connect the coil wire back up. It should not shut off. That will verify that your switches are most likely OK.

little update... i found a bad wire that was under the flywheel. i repaired the wire and the mower still does the same thing. the wire is for the coil grounding circuit... I also figured out that if i disconnect head lights the mower fires right up but will not shut off until i plug the headlights back in. im assuming this is the circuit with my issue at this point. also the headlights are ran through the ignition switch.

thanks

"I also figured out that if i disconnect head lights the mower fires right up but will not shut off until i plug the headlights back in."

I think you still must have the wrong key switch!

X2 on that. The switch is wrong. Deere AM119111 is the right switch.