Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!

JaimesBeam

Forum Newbie
Joined
May 30, 2011
Threads
1
Messages
1
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
My Sears Craftmans Riding Mower Won't Start!!!

It's a 12.5 HP 42" Riding Lawn Tractor Model 917.2555.81. I don't know the year. (old!)
Originally the Power Terminal from the Starter Relay on the Starter cracked and was shorting.
Took the Starter apart and repaired it with Gorilla Epoxy and Electrical Tape. Yeah! The Starter
works when connected to a battery when mounted on the engine! But there still seems to be some problem with the Starter Switch, or the Starter Relay/Solenoid.
Both of the parts are available from Sears Parts Online. But I don't want to order the parts untill I've
definitively proved which parts is bad, and probably gotten the mower to start by bypassing it.

I found a circuit diagram for the mower at:

http://home.comcast.net/~tommyspace/Images/917-255581med.pdf

which is great... I will probably bypass all the safety interlocks to make it easy to diagnose...

The question I have is about terminal M on the Ignition Switch. It appears to be connecting to ground
under various conditions: (Seat Switch Not Occupied), (Attachment Clutch Off), (Key Switch Off).
This puzzles me because it apparently connects the ignition module to ground when (Key Switch Off)
or ((Seat Switch Not Occupied) and (Attachment Clutch On)). Which makes sense as far as that goes,
but what about when ((Seat Switch Occupied) and (Attachment Clutch On)), or (Seat Switch Not Occupied) and (Attachment Clutch Off))? You want the mower to not start in all these conditions, and
only start when (Key Switch On) and (Seat Switch Occupied) and (Attachment Clutch Off)!

If the wiring is actually wired this why, I don't see it resulting in the desired Behavior; only starting when the last set of conditions are true.

The other issue is that I don't see anything other then Black/Ground being connected to the Ignition
module and spark plug; it seems to me like there needs to be a connection to power somewhere
there!!! I would think that Terminal M should connect the Ignition Module to Power at least during the
right starting conditions!!! But that's not what the circuit diagram seems to say!!!

Also the Ignition Switch Table doesn't seem to say anything about turning on Terminal M to the
Ignition Module when the Key Switch is in the On or Start positions. It seems to just say that it isn't
Grounded when ((Key Switch (On or Start)) Or (Seat Switch Occupied) Or (Attachment Clutch Off)).

This implies that I should be able to get this to run merely by clipping the Black wire on Terminal M
to the (Attachment Clutch Switch) and (Seat Switch). This leaves the Ignition Module Grounded only
when the Key Switch is Off; Which sounds like usefull behavior.

Am I reading this Right??? I'll try it tomorrow!

Thanks, Jaimes Beam, Franklin ME
 

Attachments

  • 917-255581med.pdf
    493.2 KB · Views: 38

Briana

Lawn Addict
Joined
Jul 23, 2010
Threads
22
Messages
1,550
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
Hey there! WELCOME to LawnMowerForum! :biggrin:

I moved your thread to the Craftsman Forum. You'll get a better response there. :thumbsup:
 

ILENGINE

Lawn Pro
Joined
May 6, 2010
Threads
39
Messages
9,865
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
if you put 12v to the ground terminal of the ignition module even momentarily it will fry the module and have to be replaced. murray had a problem with bad key switches a few years back that was shorting to the m terminal on the key switch and burning out the module. briggs will not even warranty an module damaged by power input. the module is basically a generator
 

George G

Forum Newbie
Joined
May 7, 2010
Threads
0
Messages
4
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
Looking at the print. I would say the ignition unit is a magneto, when it is grounded, its like holding a screwdriver from the sparkplug to the metal on the engine. That gives a dirrect path for the electric to flow to ground(no spark).
To start. Assuming you have power on terminal B at the ignition switch. When you turn the key, power(electric) will go from terminal B to terminal S. Down the white wire to the Clutch/Brake pedal. The Clutch/Brake pedal has to be pushed in so the power can make its way to the Att'ment Clutch. The Att'ment Clutch has to be off so that the power can continue on its way to the Starter Solenoid. When power gets to the Solenoid. "If the Solenoids coil is properly grounded" it will energize the Solenoid, close the contact on the Red wire,sending power on its way to the starter. At this point, the starter should start turning.
 

trebor

Forum Newbie
Joined
Jun 12, 2011
Threads
0
Messages
1
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
Hey there! WELCOME to LawnMowerForum! :biggrin:

I moved your thread to the Craftsman Forum. You'll get a better response there. :thumbsup:

i have a craftsman zts 7500 zero turn mower that will start but shuts off immediatly.can some one help
 

KennyV

Lawn Pro
Joined
May 5, 2010
Threads
26
Messages
5,447
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
i have a craftsman zts 7500 zero turn mower that will start but shuts off immediatly.can some one help

Hello & Welcome to LMF...
You need to start a new post in This, Craftsman Forum....
It will just get lost inside this thread... :smile:KennyV
 

mr.sky

Forum Newbie
Joined
Sep 19, 2011
Threads
1
Messages
6
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
My Sears Craftmans Riding Mower Won't Start!!!

It's a 12.5 HP 42" Riding Lawn Tractor Model 917.2555.81. I don't know the year. (old!)
Originally the Power Terminal from the Starter Relay on the Starter cracked and was shorting.
Took the Starter apart and repaired it with Gorilla Epoxy and Electrical Tape. Yeah! The Starter
works when connected to a battery when mounted on the engine! But there still seems to be some problem with the Starter Switch, or the Starter Relay/Solenoid.
Both of the parts are available from Sears Parts Online. But I don't want to order the parts untill I've
definitively proved which parts is bad, and probably gotten the mower to start by bypassing it.

I found a circuit diagram for the mower at:

http://home.comcast.net/~tommyspace/Images/917-255581med.pdf

which is great... I will probably bypass all the safety interlocks to make it easy to diagnose...

The question I have is about terminal M on the Ignition Switch. It appears to be connecting to ground
under various conditions: (Seat Switch Not Occupied), (Attachment Clutch Off), (Key Switch Off).
This puzzles me because it apparently connects the ignition module to ground when (Key Switch Off)
or ((Seat Switch Not Occupied) and (Attachment Clutch On)). Which makes sense as far as that goes,
but what about when ((Seat Switch Occupied) and (Attachment Clutch On)), or (Seat Switch Not Occupied) and (Attachment Clutch Off))? You want the mower to not start in all these conditions, and
only start when (Key Switch On) and (Seat Switch Occupied) and (Attachment Clutch Off)!

If the wiring is actually wired this why, I don't see it resulting in the desired Behavior; only starting when the last set of conditions are true.

The other issue is that I don't see anything other then Black/Ground being connected to the Ignition
module and spark plug; it seems to me like there needs to be a connection to power somewhere
there!!! I would think that Terminal M should connect the Ignition Module to Power at least during the
right starting conditions!!! But that's not what the circuit diagram seems to say!!!

Also the Ignition Switch Table doesn't seem to say anything about turning on Terminal M to the
Ignition Module when the Key Switch is in the On or Start positions. It seems to just say that it isn't
Grounded when ((Key Switch (On or Start)) Or (Seat Switch Occupied) Or (Attachment Clutch Off)).

This implies that I should be able to get this to run merely by clipping the Black wire on Terminal M
to the (Attachment Clutch Switch) and (Seat Switch). This leaves the Ignition Module Grounded only
when the Key Switch is Off; Which sounds like usefull behavior.

Am I reading this Right??? I'll try it tomorrow!

Thanks, Jaimes Beam, Franklin ME

Where did you find the Schematic? I need one for model 917270821
 

mr.sky

Forum Newbie
Joined
Sep 19, 2011
Threads
1
Messages
6
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!

dantheman

Forum Newbie
Joined
Sep 20, 2011
Threads
1
Messages
5
  • / Sears Craftsman Mower Won't Start??? Funky Switch Circuit Diagram!!!
Thanks but I have that already, what I need to know which wires go to solenoid. someone took
it apart, and did not mark which wires go to solenoid.

mr. sky I meant to look in the back of the owners manual it has the circuit diagram. I attached the pdf. The circuit wires are color coded and their connections. Hope I was of help.
 

Attachments

  • 917270821.pdf
    3.4 MB · Views: 42
Top