2 Pack 311280001 Start Key Compatible with Ryobi 40V Lawn Mower, 311280001 Fuse Key for P1100 RY40104 RY40108 RY40109

What It Is

This is a 2-pack of 311280001 start keys (fuse keys) designed to replace the safety key on Ryobi 40V cordless lawn mowers. The key acts as a circuit breaker and safety interlock—without it inserted, the mower won’t start. It’s a direct replacement for lost, broken, or worn-out original keys on compatible Ryobi models.

Fitment & Compatibility

Before buying, confirm your mower’s model number. This key fits Ryobi 40V mowers that use the 311280001 part number, including:

• P1100
• RY40104
• RY40108
• RY40109
• RY401140
• RY401150
• RY401160

Check your mower’s battery compartment or under the handle for a sticker listing the model number. Measure the key slot dimensions if you have an old key—this key is about 1.5 inches long and 0.5 inches wide with a rectangular blade. It will not fit Ryobi 18V mowers or 40V models that use a different key shape (e.g., RY40180 or RY40190). This is an aftermarket replacement, not OEM Ryobi, but uses the same plastic and metal contacts as the original.

Key Things to Know

• Quality: Most users report a snug fit and reliable electrical contact. A few note the plastic feels slightly thinner than OEM, but still functions for normal use.
• Installation: Zero difficulty—just slide the key fully into the slot until it clicks. No tools needed.
• Gotchas: If your mower still won’t start after inserting the key, check the battery charge and the mower’s safety switch (e.g., handle bail must be pressed). The key itself is a simple pass-through, so it rarely causes starting issues.
• Value: The 2-pack is cheaper than a single OEM key (often $8–10), making it a good backup to keep in your garage or shed.

Should You Buy It

Buy this if you’ve lost your original Ryobi 40V mower key, or want a spare to keep in your tool bag. It’s a low-cost, drop-in fix for the models listed, and the 2-pack gives you a backup for under $8. If you have a different Ryobi model or want an OEM part for peace of mind, skip this and order directly from Ryobi.