My 2001 Walker MTGHS Serial No.
51338 with very low miles and well maintained died abruptly after mowing an
hour. It was as if I killed the engine (Kohler CH20S, 64554). It started right
back up and then died again. It would not start after that. When it runs it
runs well. When it dies it is as if I turned it off.

I first checked the safety
interlocks. All three are in working order. After testing and ensuring that the
starter and solenoid were both good, I started the engine. It fired up easily
and ran well for 10 minutes then died as before. The next day it started fine
and I mowed for about 45 minutes before it died again. It would not restart that
time after dying, only sounding oil pressure and temp alerts. Now, I can start
the engine and it will run for a few minutes before dying.

I know it sounds like a fuel
delivery issue but I really think it is an electrical short issue based upon
what I have done:

1. Fuel

pump is working properly. Bowl is filling and sending fuel to chambers. Sparks
present, plugs wet. And fuel shutoff solenoid working. Therefore do not believe
it is a fuel delivery issue.

2. Even

though the start circuit (key) energizes the fuel shutoff plunger, it only
reads 6.5v at the solenoid. Therefore, I fed the solenoid 12 volts directly
from the battery to see if that might be the problem. It apparently did not
change anything. Can still start the engine but it will die after 3-5 minutes
of run time.

3. If

I turn key to RUN position, without starting the engine, the oil temp and oil pressure
lamps both sound the horn. And the voltage meter would not work, which is
atypical. Typically for 16 years upon starting engine only the oil pressure
light would sound until engine started. And typically the voltage meter would work
upon putting key in RUN or START.

4. What

I noticed this time when turning key to RUN, without starting the engine, is
that the RED battery and PUR accessory wire out of the ignition switch became
extremely hot (and would emit electrical burn odor). This made me believe that
I had a short in the electrical system. I replaced the 30 amp auto reset
breaker and began testing the electrical circuit.

5. First

tested the IGNITION SWITCH and it is not internally shorted.

6. At

the IGNITION SWITCH I am getting 12.63v at “B” RED battery wire.

7. At

the IGNITION SWITCH I am getting 12.63v across “B” + “A” (PUR accessory wire).

8. At

the chassis plug that feeds starter and engine components, I am getting 12.63v
at PUR wire and at the BLU wire when IGNITION SWITCH is in RUN.

9. At

the chassis plug that feeds starter and engine components I am getting 12.63v
across YEL wire when moving IGNITION to START.

10. All
    this tells me that the START RELAY is working properly. Nothing surprising so far.

11. De-energized
    system and began testing short to ground on the wires at different intervals:

12. At IGNITION
    SWITCH, going through START RELAY, with 5-pin DISCONNECTED from engine, light accessory
    disconnected and delay relay disconnected NO SHORTS except black wire.

13. At IGNITION
    SWITCH, going through START RELAY, with 5-pin CONNECTED to engine, everything
    else same as no. 12, the PUR wire shorted as well as the BLK.

14. At
    console, testing 8-PIN CONNECTOR, with ENGINE CONNECTED, and delay and lights disconnected,
    it yields SHORTS at PUR, YEL, BLU, BLK and GRN. NO SHORTS at RED, WHI and GRA. If
    I plug in the lights, then the GRA would short at same test site.

15. FROM
    8-PIN TO 5-PIN plug going to engine, ALL SHORT EXCEPT WHI. SHORTED ARE two BLK
    wires (shrink wrapped – maybe containing diode to stator), PUR wire, BLU wire
    to solenoid and RED wire.

16. All
    the above continuity tests were performed with lights and delay relay isolated.

17. With
    delay relay connected, then WHI shorts at the ignition switch, everything else
    connected except for the lights, and the BRN/WHT to Neutral Switch shorts.

The only component I have not
isolated and tested is the time delay module. I have independently tested the
three relays and they are functioning properly. I have also checked and rechecked all grounds
and they appear good. Based upon the tests, it seems that the PUR to the voltage
regulator is acting up intermittently. Maybe loose but haven’t had time to pull
engine to remove cover to get to VR.

Attached (I think) at page 95 is the Wiring Schematic for this Serial No. Walker. the only difference is that the circuit breaker controlling the gauges and safety interlocks is a 7a fuse not a 5a. I can send a service manual if helpful.

I’m sure I’ve missed something. I really appreciate the help diagnosing this
issue. Thank you.

PS Well guess I'm not smart enough to upload the wiring schematic. I can email or it can be found at http://www.walker.com/manuals/  select: T- Series Mower 06/01/2002 49592-71496. What an inconvenience. My apologies.