BioLion Carburetor Kit for 125cc–140cc 300E/450E/500E/550E Engines — Includes 799579 Air Filter & Primer Bulb

BioLion 799583 is a direct-replacement carburetor kit (includes 799579 air filter) engineered to restore reliable starting, smooth acceleration, and reduced smoke for 125cc–140cc 300E/450E/500E/550E series lawnmower engines.

If your mower struggles to start, idles roughly, or emits excessive smoke, a worn or clogged carburetor and air filter are often the cause. This complete kit supplies the 799583 carburetor plus essential installation parts so you can return a compatible 300E/450E/500E/550E engine to dependable operation without buying a costly replacement unit.

Will this carburetor fit my engine model?

This kit is designed for a range of small engine models commonly found on lawn mowers and outdoor power equipment. Confirm fit by checking the original part numbers or engine designation before ordering to avoid compatibility issues.

• Replaces part numbers: 799583, 595656, 590556, 591160, 591979, 593261
• Fits engine series: 300E, 450E, 500E, 550E and variants 09P602, 08P502, 9P602, 8P502
• Intended for 125cc and 140cc single-cylinder engines
• Verify your mower’s engine model and original carburetor part number before installing

How does installation and setup work?

The kit arrives with the main carburetor and the small parts you’ll need for replacement, reducing downtime and trips to the parts store. Basic hand tools are sufficient for most installs; if you aren’t comfortable with small-engine work, a quick service from a local technician is inexpensive and fast.

• Included components: carburetor, two gaskets, two clamps, fuel filter, primer bulb, spark plug, spring, and the 799579 air filter
• Typical install time: about 30–60 minutes for someone with basic mechanical skill
• No specialized calibration equipment required for standard replacements
• Inspect hoses, seals, and mounting points while installing to ensure leak-free performance

What performance improvements can I expect?

Replacing a failing carburetor and air filter can eliminate hard-starting, surging, and black exhaust smoke while restoring steady throttle response. The kit aims to return the engine to factory-like fuel delivery and combustion characteristics when installed correctly.

• Better cold starts thanks to included primer bulb and tuned carburetor parts
• Smoother idling and more responsive acceleration under load
• Reduced oil and carbon-rich smoke from improved air-fuel mixture
• Longer engine life when carbs and filters are maintained regularly

What’s included in the kit and why those parts matter?

Beyond the primary replacement carburetor, the kit contains small consumables that commonly wear or break during removal and reinstallation. Supplying these parts avoids mismatches and lets you complete the job in one visit.

• 799583 carburetor: main replacement unit matched to listed part numbers
• 799579 air filter: fresh filtration to prevent dirt ingestion
• Fuel filter and clamps: ensure clean fuel flow and secure lines
• Gaskets, primer bulb, spark plug, and spring: necessary for leak-free, functional assembly

Who is this for: This carburetor kit is aimed at homeowners, landscapers, and small-equipment mechanics who maintain 125cc–140cc lawnmowers and need a reliable replacement without sourcing multiple separate parts. It’s ideal for anyone troubleshooting hard starts, unstable idle, acceleration problems, or heavy smoke on compatible 300E/450E/500E/550E engines and who prefers a ready-to-install kit to get equipment back in service quickly.