When your tractor’s Onan engine starts running rough or takes more pulls to start, there’s a good chance it’s time for a new spark plug. This Autolite 437 is designed specifically for Onan B43M and B48M engines, delivering the hot heat range these air-cooled workhorses need to fire reliably and keep you moving through your tasks.
What You’re Getting
- Hot heat range designed for optimal performance in Onan air-cooled engines
- Power tip design for improved combustion and easier starting
- Non-resistor construction that works with older ignition systems
- Standard 14mm threads with 7/16 inch reach for proper fit
- 13/16 inch hex makes installation straightforward with common tools
Built for Real Farm Work
This plug fits Onan B43M and B48M engines commonly found in Bolens, Massey Ferguson, and Case equipment from the era when these reliable twin-cylinder engines powered everything from garden tractors to small utility machines. If you’re running older equipment that’s still earning its keep around the farm, this is the plug that’ll keep it running strong.
Made to Last
Autolite plugs are built to handle the heat cycles and vibration that come with air-cooled engine operation. The hot heat range helps burn off carbon deposits that can build up during lighter-duty operation, while the power tip design improves spark energy for reliable ignition even as the plug ages.
Good to Know
Installation is straightforward—just gap to your engine’s specs (usually around .025 inches for these Onan engines) and thread it in finger-tight, then snug with a wrench. Don’t overtighten, as the 14mm threads can be damaged. If you’re cross-referencing, this plug matches up with Champion H14Y or H18Y plugs.
