Troy bilt pony will not start. replaced 20 amp fuse and battery

OK -- Here's what to do:
TROY-BILT PONY LT CRANKING CIRCUIT TROUBLESHOOTING

NOTE 1: The following tests are to be made with the parking brake applied and the PTO disengaged unless otherwise specified.

NOTE 2: These tests need only be made until the cause of the problem is located. The entire process need not be completed if the problem has been resolved.

NOTE 3: Refer to the wiring diagram below for understanding of all tersts.

NOTE 4: Wiring Diagram references to Key switch A1 and L terminals refer to the same terminal.

1. With all circuits connected normally, connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the battery positive terminal. The voltmeter should read at least +12.6 VDC.
a. If NO, go to step 2.
b. If YES, go to Step 3.

2. Connect a DC voltemeter directly across the battery. The voltmeter should read at least 12.6 VDC.
a. If NO, charge or replace the battery.
b. If YES, check and repair/replace the following items as required, then repeat Step 2 test. If YES on retest, go to Step 3.
-- battery negative cable condition
-- battery negative cable connections at the battery
-- battery negative cable connections at the tractor frame

3. With all circuits connected normally, connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the key swttch "B" terminal (Circuit #97 - red/white wire). The voltmeter should read at least +12.6 VDC.
a. If NO, go to step 4.
b. If YES, go to Step 8.

4. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the starter relay BAT terminal (Circuit #94 - heavy red wire). The voltmeter should read at least +12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 4 test. If YES on retest, go to Step 5.
-- battery positive cable condition
-- battery positive cable connections at the battery
-- battery positive cable connection at the starter relay
b. If YES, go to Step 5.

5. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the fuse holder BAT terminal (Circuit #92 - red wire). The voltmeter should read at least +12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 5 test. If YES on retest, go to Step 6.
-- Circuit 92 wire condition
-- Circuit 92 wire connection at the starter relay
-- Circuit 92 wire connection at the fuse holder
b. If YES, go to Step 6.

6. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the fuse holder protected circuit terminal (Circuit #97 - red & white wire). The voltmeter should read at least +12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 6 test. If YES on retest, go to Step 7.
-- 20A fuse condition
-- fuse holder condition
-- fuse holder wire connections
b. If YES, go to Step 7.

7. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the key switch "B" terminal (Circuit #97 - red & white wire). The voltmeter should read at least +12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 7 test. If YES on retest, go to Step 8.
-- Circuit 97 wire condition
-- Circuit 97 connection at fuse holdser
-- Circuit 97 connection at key switch
b. If YES, go to Step 8.

8. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the key switch "S" terminal (Circuit #80 - orange wire). With the key held in the START position, the voltmeter should read at least +12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 8 test. If YES on retest, go to Step 9.
-- key switch assembly
b. If YES, go to Step 9.

9. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the parking brake switch Circuit #80 terminal (Circuit #80 - orange wire). With the key held in the START position, the voltmeter should read at least +12.6
VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 9 test. If YES on retest, go to Step 10.
-- Circuit 80 wire condition
-- Circuit 80 connection at key switch
-- Circuit 80 connection at parking brake switch
b. If YES, go to Step 10.

10. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the parking brake switch Circuit #70 terminal (Circuit #70 - orange & black wire). With the key held in the START position, the voltmeter should read at
least +12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 10 test. If YES on retest, go to Step 11.
-- parking brake switch assembly mounting and adjustment
-- parking brake switch assembly condition
b. If YES, go to Step 11.

11. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the PTO switch Circuit #70 terminal (Circuit #70 - orange & black wire). With the key held in the START position, the voltmeter should read at least +12.6
VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 11 test. If YES on retest, go to Step 12.
-- Circuit 70 wire condition
-- Circuit 70 connection at parking brake switch
-- Circuit 70 connection at PTO switch
b. If YES, go to Step 12.

12. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the PTO switch Circuit #60 terminal (Circuit #60 - orange & white wire). With the key held in the START position, the voltmeter should read at least +12.6
VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 12 test. If YES on retest, go to Step 13.
-- PTO switch assembly mounting and adjustment
-- PTO switch assembly condition
b. If YES, go to Step 13.

13. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the starter relay Circuit #60 terminal (Circuit #60 - orange & white wire). With the key held in the START position, the voltmeter should read at least
+12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 11 test. If YES on retest, go to Step 14.
-- Circuit 60 wire condition
-- Circuit 60 connection at PTO switch
-- Circuit 60 connection at starter relay
b. If YES, go to Step 14.

14. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the starter relay MOT terminal (Circuit #93 - heavy red wire). With the key held in the START position, the voltmeter should read at least +12.6 VDC.
a. If NO, did the relay make a single heavy "click" noise?
1. if YES, replace the starter relay and repeat Step 14 test. If YES on retest, go to Step 15.
2. If NO, connect a DC voltmeter DC voltmeter black (NEG) lead to the battery negative terminal and the red (POS) lead to the starter relay frame. With the key held in the START position, the voltmeter should read a maximum of +0.1 VDC.
a. If YES, replace the starter relay and repeat Step 14 test. If YES on retest, go to Step 15.
b. If NO, check and repair/replace the following items as required, then repeat Step 14 test. If YES on retest, go to Step 15.
-- starter relay mounting
b. If YES, go to Step 15.

15. Connect a DC voltmeter black (NEG) lead to the tractor frame and the red (POS) lead to the starter motor BAT terminal (Circuit #93 - heavy red wire). With the key held in the START position, the voltmeter should read at least +12.6 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 15 test. If YES on retest, but the starter motor does not engage, go to Step 16.
-- Circuit 93 cable condition
-- Circuit 93 cable connection at starter relay
-- Circuit 93 cable connection at starter motor
b. If YES, but the starter motor does not engage, go to Step 16.

16. Connect a DC voltmeter black (NEG) lead to the battery negative terminal and the red (POS) lead to the starter motor frame . With the key held in the START position, the voltmeter should read a maximum of +0.2 VDC.
a. If NO, check and repair/replace the following items as required, then repeat Step 16 test. If YES on retest, but the starter motor does not engage, go to Step 16b.
-- starter motor mounting to engine
-- engine mounting to tractor frame
b. If YES, but the starter motor does not engage, replace the starter motor.


REFERENCE PART NUMBERS PER WIRING DIAGRAM:

Note that your specific tractor may use differnt part numbers. You can obtain a Parts List specific to your tractor online, at no charge, from Troy-Bilt at www.troybilt.com -- your full model number and serial number are required.

Key Switch 725-04228 (common alternatives are 925-04227B & 925-04659)Parking Brake Switch 725-1657A (common alternative is 725-04363)
PTO Switch 725-1657A (common alternative is 725-04363)
Starter Relay 725-04439

Also note that the starter motor is an engine manufacturer supplied part.