Carbhub carburetor replacement kit 591731 for 31H777 vertical shaft engines — includes air filter & spark plug

If your lawn tractor or zero-turn mower is running rough, hard to start, or has poor throttle response, replacing a worn carburetor can often bring it back to reliable operation. This Carbhub 591731 assembly replaces OEM part numbers such as 591731, 594593, 796109 and many others, and ships with a set of maintenance accessories to simplify installation and first start-up.

Which engines and models will this carburetor work with?

This carburetor is built for small vertical-shaft gasoline engines in the 13.5–17.5 HP range, including many 31H777, 28AH/28BH/28CH and 31A507 series blocks. It lists compatibility with a broad set of Toro lawn tractors and Cub Cadet zero-turn models, but compatibility depends on specific engine configuration and manufacture year.

• Fits engine series: 31H777, 28AH76/77, 28BH76/77, 28CH77, 31A507
• Horsepower range: 13.5HP to 17.5HP vertical shaft motors
• Compatible machines: select Toro tractors (models 71286, 71427–71429, 74301, 74325, 74327, 74330) and several Cub Cadet RZT and LT series
• Check engine serial and build year to confirm fit before ordering

What parts are included and how does the upgraded kit help?

The package arrives as a maintenance-ready kit with the carburetor plus common consumables so you can replace the unit and refresh fuel and ignition components in one session. The updated kit includes additional clamps and hoses compared with older versions, reducing the chance you'll need extra parts mid-install.

• Included: 1 carburetor, 1 air filter, 1 spark plug, 1 fuel filter, 1 gasket
• Included accessories: 8 clamps, 2 fuel lines, 1 fuel shut-off valve
• Updated kit note: if you receive an older configuration, contact the seller for support
• Saves time by bundling common replacement parts for a single service visit

How difficult is the installation and what should you prepare?

Installation is a moderate DIY task for someone familiar with small engine work; basic hand tools, a clean workspace, and safety precautions are required. If you are inexperienced, having a repair manual or photos of the old setup helps; the included gasket, lines, and clamps are sized to match common OEM fittings.

• Tools typically needed: screwdrivers, pliers, socket set, carb cleaner
• Prep: drain fuel or work with minimal tank fuel, disconnect battery if present
• Verify hose routing and throttle/choke linkages match the original before final tightening
• Consider a torque spec guide or professional help for complex tractors

Who is this for: This Carbhub 591731 replacement is intended for homeowners, landscapers, and small-engine technicians who need a dependable carburetor swap for Toro and Cub Cadet machines built around the listed engine families. It’s ideal if you want a single-purchase solution that includes the carburetor plus common consumables—handy for seasonal maintenance or restoring equipment after fuel-related wear. Always confirm part numbers and build year (note: the 594593 variant is for models made in 2015 and later) before installing to ensure compatibility.