1. Transmission problem: The transmission in your lawnmower is responsible for transferring power from the engine to the wheels. If the transmission is damaged or malfunctioning, it can cause the lawnmower to only run in neutral.
2. Clutch problem: The clutch is a part of the transmission that engages and disengages the power from the engine to the transmission. If the clutch is slipping or not engaging properly, it can cause the lawnmower to only run in neutral.
3. Gearshift linkage problem: The gearshift linkage is the mechanism that connects the gearshift lever to the transmission. If the gearshift linkage is damaged or disconnected, it can cause the lawnmower to only run in neutral.
4. Neutral safety switch problem: The neutral safety switch is a safety feature that prevents the lawnmower from starting in gear. If the neutral safety switch is malfunctioning, it can cause the lawnmower to only run in neutral.
Solution:
1. Inspect the transmission: Inspect the transmission for any damage or leaks. If you find any damage, you will need to repair or replace the transmission.
2. Inspect the clutch: Inspect the clutch for any signs of wear or damage. If the clutch is worn out or damaged, you will need to replace it.
3. Inspect the gearshift linkage: Inspect the gearshift linkage for any damage or disconnections. If you find any damage, you will need to repair or replace the gearshift linkage.
4. Inspect the neutral safety switch: Inspect the neutral safety switch for any damage or loose connections. If you find any damage, you will need to repair or replace the neutral safety switch.
If you are not comfortable performing these repairs yourself, you can take your lawnmower to a qualified repair shop.