Brand: BIGDOG MOWER CO.
Category: Lawn Mower
Manual Type:
Language:
Manual for ALPHA MPX - Troubleshooting and error codes + PDF Download
Uploaded: April 8, 2025, 3:07 a.m.
Warranty Summary
Warranty repair must be performed by a BigDog® Mowers Authorized Dealer before warranty credit can be allowed.
Pre-Operation:
- Check tire pressure.
- Check fuel and oil levels.
- Ensure safety interlock system is working.
- Sharpen blades and ensure they are securely fastened.
Operation:
- Sit on the operator's seat before starting.
- Move control levers to neutral/brake position.
- Always maintain a safe distance from people and pets.
- Be aware of surroundings, especially when backing up.
Safe Operation:
- Refer to the operator's manual for complete safety information.
- Never leave the machine unattended, especially with children around.
- Keep safety shields and covers in place.
Troubleshooting and error codes
| SYMPTOMS | PROBABLE CAUSES | SUGGESTED REMEDIES |
|---|---|---|
| Starting motor does not crank | Steering control levers not in park brake position or switch not adjusted | Place steering control levers in park brake position or re-adjust switch |
| Deck clutch switch engaged | Disengage clutch switch | |
| Weak or dead battery | Recharge or replace | |
| Electrical connections are corroded or loose | Check the electrical connections | |
| 15 amp fuse is blown | Replace the 15 amp fuse | |
| For additional causes | See engine manual | |
| The engine will not start, starts hard or fails to keep running | No fuel or line plugged | Fill tank or replace line (See Fuel System section for more details) |
| There is incorrect fuel in the fuel system | Drain the tank and replace the fuel with the proper type | |
| There is dirt in the fuel filter | Replace the fuel filter | |
| Dirt, water or stale fuel in the fuel system | Contact your Dealer | |
| The choke is not on (if equipped) | Move the choke lever to ON | |
| Numerous | See engine manual | |
| Engine: Runs with continuous misfiring or engine runs unevenly or erratically | Numerous | See engine manual |
| Loss of power or system will not operate in either direction | Restrictions in air cleaner | Service air cleaner |
| Poor compression | Contact your Dealer | |
| Steering linkage needs adjustment | Adjust linkage | |
| Tow valve open | Close tow valve | |
| The traction drive belt is worn, loose or broken | Install a new traction drive belt | |
| For additional causes | See engine manual | |
| Air cooled engine over- heating | Air intake screen or cooling fins clogged | Clean screen and fins |
| For additional causes | See engine manual | |
| Low engine oil pressure | Low oil level | Add oil |
| Oil diluted or too light | Change oil and check for source of contamination | |
| Failed oil pump | Contact your Dealer | |
| High oil consumption | Numerous | Contact your Dealer |
| Mower jerky when start- ing or operates in one direction only | Steering control linkage needs adjustment | Adjust linkage |
| Loose steering linkage | Tighten linkage | |
| Transaxle component faulty | Contact your Dealer | |
| Mower creeps when steering control levers are in neutral | Steering linkage needs adjustment | Adjust linkage |
| Mower circles or veers in one direction | Steering linkage needs adjustment | Adjust linkage |
| Loose steering linkage | Tighten linkage | |
| Tires improperly inflated | Adjust air pressure to 8–12 psi (55–83 kPa) | |
| Transaxle component faulty | Contact your Dealer | |
| Mower creeps when parking brake engaged | Steering linkage out of adjustment | Adjust steering linkage |
| Brakes need adjustment | Adjust parking brakes | |
| There is abnormal vibration | The engine mounting bolts are loose | Tighten the engine mounting bolts |
| The engine pulley, idler pulley or blade pulley is loose | Tighten the appropriate pulley | |
| The engine pulley is damaged | Contact your Dealer | |
| The cutting blade(s) is/are bent or unbalanced | Install new cutting blade(s) | |
| A blade mounting bolt is loose | Tighten the blade mounting bolt | |
| Spindle bearing is worn or loose | Replace or tighten spindle bearing | |
| A blade spindle is bent | Contact your Dealer | |
| Blades do not rotate | The deck drive belt is worn, loose or broken | Install a new deck drive belt |
| The deck drive belt is off the pulley | Install the deck drive belt and check for a reason | |
| Electric clutch is not engaging | Check and/or replace 15 amp fuse. Contact your Dealer | |
| Uneven cutting height | The blade(s) are not sharp. | Sharpen the blades |
| A cutting blade(s) is/are bent | Install new cutting blade(s) | |
| The deck is not level | Level the deck per the Deck leveling section of the General Service Manual | |
| An anti-scalp wheel is not set correctly | Adjust the height of the anti-scalp wheel | |
| The underside of the deck is dirty | Clean the underside of the deck | |
| Tires improperly inflated | Adjust air pressure to 8–12 psi (55–83 kPa) | |
| A blade spindle is bent | Contact your Dealer | |
| Flex Forks® are installed | After initial break-in period, level the deck per the Deck Leveling section of the General Service Manual |
Troubleshooting and error codes
| SYMPTOMS | PROBABLE CAUSES | SUGGESTED REMEDIES |
|---|---|---|
| Starting motor does not crank | Steering control levers not in park brake position or switch not adjusted | Place steering control levers in park brake position or re-adjust switch |
| Deck clutch switch engaged | Disengage clutch switch | |
| Weak or dead battery | Recharge or replace | |
| Electrical connections are corroded or loose | Check the electrical connections | |
| 15 amp fuse is blown | Replace the 15 amp fuse | |
| For additional causes | See engine manual | |
| The engine will not start, starts hard or fails to keep running | No fuel or line plugged | Fill tank or replace line (See Fuel System section for more details) |
| There is incorrect fuel in the fuel system | Drain the tank and replace the fuel with the proper type | |
| There is dirt in the fuel filter | Replace the fuel filter | |
| Dirt, water or stale fuel in the fuel system | Contact your Dealer | |
| The choke is not on (if equipped) | Move the choke lever to ON | |
| Numerous | See engine manual | |
| Engine: Runs with continuous misfiring or engine runs unevenly or erratically | Numerous | See engine manual |
| Loss of power or system will not operate in either direction | Restrictions in air cleaner | Service air cleaner |
| Poor compression | Contact your Dealer | |
| Steering linkage needs adjustment | Adjust linkage | |
| Tow valve open | Close tow valve | |
| The traction drive belt is worn, loose or broken | Install a new traction drive belt | |
| For additional causes | See engine manual | |
| Air cooled engine over- heating | Air intake screen or cooling fins clogged | Clean screen and fins |
| For additional causes | See engine manual | |
| Low engine oil pressure | Low oil level | Add oil |
| Oil diluted or too light | Change oil and check for source of contamination | |
| Failed oil pump | Contact your Dealer | |
| High oil consumption | Numerous | Contact your Dealer |
| Mower jerky when start- ing or operates in one direction only | Steering control linkage needs adjustment | Adjust linkage |
| Loose steering linkage | Tighten linkage | |
| Transaxle component faulty | Contact your Dealer | |
| Mower creeps when steering control levers are in neutral | Steering linkage needs adjustment | Adjust linkage |
| Mower circles or veers in one direction | Steering linkage needs adjustment | Adjust linkage |
| Loose steering linkage | Tighten linkage | |
| Tires improperly inflated | Adjust air pressure to 8–12 psi (55–83 kPa) | |
| Transaxle component faulty | Contact your Dealer | |
| Mower creeps when parking brake engaged | Steering linkage out of adjustment | Adjust steering linkage |
| Brakes need adjustment | Adjust parking brakes | |
| There is abnormal vibration | The engine mounting bolts are loose | Tighten the engine mounting bolts |
| The engine pulley, idler pulley or blade pulley is loose | Tighten the appropriate pulley | |
| The engine pulley is damaged | Contact your Dealer | |
| The cutting blade(s) is/are bent or unbalanced | Install new cutting blade(s) | |
| A blade mounting bolt is loose | Tighten the blade mounting bolt | |
| Spindle bearing is worn or loose | Replace or tighten spindle bearing | |
| A blade spindle is bent | Contact your Dealer | |
| Blades do not rotate | The deck drive belt is worn, loose or broken | Install a new deck drive belt |
| The deck drive belt is off the pulley | Install the deck drive belt and check for a reason | |
| Electric clutch is not engaging | Check and/or replace 15 amp fuse. Contact your Dealer | |
| Uneven cutting height | The blade(s) are not sharp. | Sharpen the blades |
| A cutting blade(s) is/are bent | Install new cutting blade(s) | |
| The deck is not level | Level the deck per the Deck leveling section of the General Service Manual | |
| An anti-scalp wheel is not set correctly | Adjust the height of the anti-scalp wheel | |
| The underside of the deck is dirty | Clean the underside of the deck | |
| Tires improperly inflated | Adjust air pressure to 8–12 psi (55–83 kPa) | |
| A blade spindle is bent | Contact your Dealer | |
| Flex Forks® are installed | After initial break-in period, level the deck per the Deck Leveling section of the General Service Manual |