Carbhub Carburetor Replacement Kit 591731 for 13.5–17.5HP Engines — Complete Kit with Air & Fuel Filters, Spark Plug

The Carbhub 591731 is a complete carburetor replacement kit built to restore fuel delivery on compatible 13.5–17.5HP vertical shaft engines and select Toro/Cub Cadet lawn tractors and zero-turn mowers.

When an aging carburetor causes hard starting, rough idling, or fuel leaks, replacing it with a matched assembly and necessary accessories is often the fastest way to get equipment back in service. This Carbhub 591731 unit is supplied with multiple fittings and consumables — air filter, spark plug, fuel filter, gasket, clamps, fuel lines, shutoff valve — so you can swap the entire fuel system interface in one repair. It’s designed to fit a long list of part numbers and engine series used by popular lawn tractor and zero-turn models.

Which models and engines will this carburetor fit?

This replacement fits a range of Briggs & Stratton–pattern vertical shaft engines identified by service series and common part numbers. It is also compatible with many Toro and Cub Cadet lawn tractors and zero-turn mowers produced in specified model years.

• Compatible engine series: 31H777, 28AH76/77, 28BH76/77, 28CH77, 31A507 and similar vertical-shaft motors.
• Power range: typical fit for 13.5HP, 14.55HP, 15HP, 16HP and 17.5HP engines.
• Listed OEM part cross-references include: 591731, 594593, 796109, 498811, 794161, 795477, 590400 and others.
• Compatible with many Toro models (e.g., 71286, 71427–71429, 74301, 74325, 74327, 74330) and Cub Cadet LT/RZT series variants.

What’s included in the package and why it matters?

The kit arrives as a ready-to-install carburetor plus the common consumables and hoses used during a typical rebuild or replacement. That saves time hunting parts and reduces the chance of missing small but essential items during reassembly.

• 1x Carburetor body matched to the listed cross-reference numbers.
• 1x Air filter and 1x fuel filter to ensure clean intake and fuel delivery on installation.
• 1x Spark plug, 1x gasket, 8x hose clamps, 2x fuel lines and 1x fuel shutoff valve for a complete refresh.

Are there compatibility or version limitations I should know about?

Yes — this carburetor is intended for machines manufactured in 2015 or later in the specified model families. Some older machines or engines with different mounting patterns or choke linkages will not accept this unit without additional modification.

• Designed for models produced 2015 onward; not compatible with pre-2015 configurations in many cases.
• If you receive an older revision of the product, contact the seller for the updated kit or guidance.
• Verify your engine’s part numbers and physical mounting before ordering to avoid fitment issues.

How should I prepare for installation and tuning?

Before starting, gather basic hand tools, have fuel drained or contained, and compare the new carburetor’s mounting, throttle, and choke linkages to the removed unit. Installation typically requires minor adjustment of idle and mixture screws after mechanical mounting and hose connections.

• Disconnect the spark plug and drain fuel from the bowl or tank for safety prior to removal.
• Match mounting studs, throttle/choke linkages and fuel line connections before tightening clamps.
• After installation, adjust idle and mixture per your engine’s service manual and test under light load.

Who is this for: The Carbhub 591731 kit is aimed at DIY lawn mower owners, small-engine mechanics, and landscapers who need a comprehensive replacement package for mid-range vertical-shaft engines used in Toro and Cub Cadet tractors and zero-turn mowers. It’s most useful when you want a single-purchase solution that includes both the carburetor and commonly replaced consumables for an efficient field repair.