698781 O-Ring Float Bowl Carburetor Gasket Replacement for Nikki Carburetor Lawn Mowers (1 Pack)

What It Is

This is a replacement O-ring gasket (part #698781) for the float bowl on a Nikki carburetor, commonly found on small engines in lawn mowers, tractors, and generators. It seals the carburetor bowl to prevent fuel leaks and air intake issues.

Fitment & Compatibility

• Check your carburetor brand: This fits Nikki carburetors specifically. Look for “Nikki” stamped on the carb body.
• OEM cross-reference: Replaces OEM part #698781. Common on Briggs & Stratton engines (e.g., 500–700 series) and some Craftsman, Husqvarna, and MTD mowers.
• Measure the O-ring: Inner diameter should be ~1.5 inches (38mm), thickness ~0.1 inches (2.5mm). If your bowl gasket is flat or a different shape, this won’t work.
• Verify engine model: Not universal—fits only engines with Nikki carbs. Check your engine model number (e.g., 12A-123-4567) and confirm carb type.

Key Things to Know

• Quality: Made of rubber/nitrile O-ring material; holds up well to fuel but can dry out over time. Not as durable as OEM gasket in some cases.
• Installation: Easy—remove carb bowl, swap old O-ring, reassemble. No special tools needed. Torque bowl screw gently to avoid stripping.
• Common gotcha: Old O-ring may be stuck or brittle. Clean carb bowl groove thoroughly before installing new one. If the carb has a flat paper gasket, this won’t seal.
• Single pack: Only one O-ring included. If you have multiple carbs or want a spare, buy more.

Should You Buy It

Buy this if you have a Nikki carb with a leaking float bowl and need a quick, cheap fix. It’s a solid budget option for DIY mower owners who can confirm the O-ring size and carb type. Skip it if your carb uses a paper gasket or if you want a longer-lasting OEM part.