UpStart Components 692046 Fuel Tank Cap Replacement for John Deere JS25 MowMentum Walk-Behind Mower - PC9737 - Compatible with 397974 M143291 Gas Cap

What It Is

This is a replacement fuel tank cap for John Deere JS25 MowMentum walk-behind mowers. It seals the fuel tank to prevent leaks and evaporation, and is designed for standard gasoline fuel systems on push mowers.

Fitment & Compatibility

• Direct OEM replacement: Fits John Deere JS25 MowMentum models using OEM parts PC9737, 397974, or M143291.
• Check your mower’s deck size: The JS25 typically has a 21-inch or 22-inch stamped steel deck—this cap fits all variants of that series.
• Measurements: Cap diameter is approximately 1.5 inches (38mm) with a standard twist-on design. Confirm your tank opening matches before ordering.
• Brand-specific: Compatible only with John Deere JS25 MowMentum; not for other JD models or brands unless explicitly cross-referenced.
• Aftermarket vs OEM: This is a non-OEM cap from UpStart Components, but rated for direct fit with no modifications needed.

Key Things to Know

• Quality: Made from plastic with a rubber gasket. Users report a snug, leak-free seal—no reported cracking or warping after several months of use.
• Installation: Tool-free—just twist off the old cap and twist on the new one. Takes under 30 seconds.
• Common gotcha: If your old cap is cross-threaded or the tank neck is damaged, the new cap may not seal properly. Inspect the tank opening for cracks or distortion before installing.
• Ventilation: This cap includes a built-in vent to prevent vacuum lock during operation. If you smell gas or see fuel weeping, check that the vent isn’t clogged.

Should You Buy It

Buy this if you own a John Deere JS25 MowMentum and need a quick, affordable replacement for a lost, cracked, or leaking gas cap. It’s a no-brainer at $5.99—just verify your current cap’s OEM part number matches one of the listed cross-references (PC9737, 397974, or M143291) to ensure a perfect fit.