Introduction
This manual provides essential information for the safe and effective operation, maintenance, and care of your RYOBI 40V HP Brushless 12-inch Top Handle Battery Chainsaw. Please read all instructions carefully before use and retain this manual for future reference.
The RYOBI 40V HP Brushless 12-inch Top Handle Chainsaw is designed for efficient cutting tasks, offering gas-like performance with the convenience of cordless operation. Its 40V HP technology and brushless motor deliver enhanced cutting speed, extended runtime, and increased motor life. The top handle design provides improved user control, making it suitable for various cutting applications.
Safety Information
Operating a chainsaw can be hazardous. Always prioritize safety to prevent serious injury. Adhere to the following general safety guidelines:
- Wear appropriate personal protective equipment (PPE), including safety glasses, hearing protection, gloves, and sturdy footwear.
- Ensure the work area is clear of bystanders, especially children and pets.
- Inspect the chainsaw before each use for any damage, loose parts, or proper chain tension and lubrication.
- Never operate the chainsaw with one hand unless specifically designed for it and you are trained to do so. This model features a top handle design for increased control.
- Be aware of kickback and how to prevent it.
- Do not operate the chainsaw in wet conditions or near flammable liquids or gases.
- Always engage the chain brake when transporting the chainsaw or when not actively cutting.
- Keep a firm grip on both handles during operation.
Package Contents
Verify that all items are present upon unpacking:
- RYOBI 40V HP Brushless 12-inch Top Handle Battery Chainsaw
- 4.0Ah Lithium-Ion Battery
- 40V Fast Charger
- 12-inch Bar and Chain
- Heavy-duty Deluxe Carrying Case
- Operator's Manual (this document)
Setup
- Charge the Battery: Insert the 4.0Ah Lithium-Ion battery into the 40V Fast Charger. Allow the battery to fully charge before first use. Refer to the charger's manual for specific charging indicators and times.
- Install Bar and Chain:
- Ensure the chainsaw is powered off and the battery is removed.
- Remove the side cover.
- Carefully place the chain around the sprocket and guide bar. Ensure the cutting edges of the chain are facing the correct direction.
- Mount the guide bar onto the studs and replace the side cover, hand-tightening the nuts.
- Adjust Chain Tension:
- Use the side access chain tensioning mechanism to adjust the chain. The chain should be snug against the guide bar but still able to be pulled freely by hand.
- Tighten the side cover nuts securely once tension is set.
- Fill with Bar and Chain Oil:
- Locate the oil reservoir cap.
- Fill the reservoir with high-quality bar and chain oil. The adjustable automatic oiler will ensure consistent lubrication during operation.
- Regularly check the oil level, as the chainsaw consumes oil during use.

A bright green and black RYOBI 40V HP Brushless 12-inch Top Handle Battery Chainsaw, shown with its 4.0 Lithium-Ion battery inserted. The chainsaw features a 12-inch bar and chain, a top handle for control, and a side access chain tensioning mechanism.
Operating Instructions
- Pre-Operation Check: Before each use, ensure the battery is fully charged, the chain is properly tensioned, the oil reservoir is full, and the chain brake is disengaged.
- Starting the Chainsaw:
- Insert the charged battery into the chainsaw.
- Ensure the chain brake is disengaged (pulled back towards the front handle).
- Grip the front handle with your left hand and the rear handle with your right hand.
- Press the safety lock-out button and then squeeze the trigger switch to start the chainsaw.
- Cutting Techniques:
- Always maintain a balanced stance and firm grip.
- Allow the chain to reach full speed before contacting the wood.
- Cut with the bottom of the guide bar for most operations.
- Be mindful of falling branches and kickback.
- Stopping the Chainsaw: Release the trigger switch to stop the chain. Engage the chain brake immediately after stopping the cut.
Maintenance
Regular maintenance ensures optimal performance and extends the life of your chainsaw.
- Chain Lubrication: The chainsaw features an adjustable automatic oiler. Regularly check the oil level and refill as needed to ensure consistent chain lubrication. Running the chainsaw without oil can cause severe damage to the bar and chain.
- Chain Tension: Periodically check the chain tension. A loose chain can derail, while an overly tight chain can cause premature wear and reduce cutting efficiency. Adjust using the side access tensioning system.
- Chain Sharpening: A sharp chain is crucial for safe and efficient cutting. Sharpen the chain regularly or replace it when dull. Refer to a specialized guide or professional service for proper sharpening techniques.
- Cleaning: After each use, remove the battery and clean the chainsaw. Clear sawdust, debris, and oil residue from the bar, chain, motor housing, and air vents.
- Storage: Store the chainsaw in its heavy-duty deluxe carrying case in a dry, secure location, out of reach of children. Remove the battery before storage.
Troubleshooting
If you encounter issues with your RYOBI chainsaw, refer to the following common troubleshooting steps:
| Problem | Possible Cause | Solution |
|---|---|---|
| Chainsaw does not start or chain does not move. | Chain brake engaged. | Ensure the chain brake is fully disengaged by pulling it back towards the front handle until it clicks. |
| Chainsaw does not start. | Battery not charged or improperly inserted. | Ensure the battery is fully charged and securely inserted into the chainsaw. |
| Poor cutting performance. | Dull chain or incorrect chain tension. | Sharpen or replace the chain. Adjust chain tension as per instructions. |
| Chain smoking or excessive heat. | Insufficient bar and chain oil. | Check oil reservoir and refill. Ensure automatic oiler is functioning. |
Specifications
- Brand: RYOBI
- Model Number: RY40590
- Power Source: Battery Powered (40V)
- Bar Length: 12 inches
- Cut Capacity: 10 inches
- Motor Type: HP Brushless
- Item Weight: Approximately 6 pounds (without battery)
- Product Dimensions: 28"L x 10"W x 10"H
- UPC: 604467576742
Warranty and Support
For warranty information, product support, or service inquiries, please contact RYOBI customer service directly. It is recommended to verify warranty coverage with the manufacturer, as policies may vary depending on the retailer and purchase conditions.





