TURBOTUNITY Carburetor Tune Up Kit for Honda GX390 27mm P27 carburetor with jets & ignition parts

The TURBOTUNITY Carburetor Tune Up Kit is a complete replacement bundle that fits Honda and compatible clone GX390 389cc/420cc engines, supplying a 27mm carburetor plus gaskets, filter, ignition parts, and upgraded jets for reliable small-engine performance.

If you maintain mini bikes, go-karts, pressure washers, pumps, log splitters or air compressors powered by Honda GX390-style engines—or compatible Harbor Freight Predator 420 units—this kit gathers the most commonly replaced components into a single boxed overhaul set. It replaces common part numbers such as 16100-ZF6-V01, 16100-ZH9-W21 and 16100-ZE2-W71 and includes a 27mm carburetor with built-in fuel tap and upgraded jets to help tune running behavior.

Will this kit fit my engine and which part numbers match?

Yes—this tune up kit is built for Honda GX390 family engines and many 389cc/420cc clones. It explicitly lists compatibility with the common OEM carburetor reference numbers and with certain Predator 420 models found in Harbor Freight equipment.

• Compatible engine types: Honda GX390, 389cc and 420cc clone engines
• Matching part numbers: 16100-ZF6-V01, 16100-ZH9-W21, 16100-ZE2-W71
• Also fits select Harbor Freight Predator 420 small engines
• Not intended for use with generators (check model fit before purchase)

What components are included and what do they address?

The package contains a P27 27mm carburetor plus the common engine parts you replace during a full tune-up. It covers fuel, air, ignition and pull-start elements so you avoid ordering multiple separate parts.

• P27 27mm carburetor with built-in fuel shutoff for easier service
• Three carburetor gaskets and two upgraded copper jets (104# and 107#)
• Air filter, spark plug, ignition coil, pull start and flameout switch
• Cylinder head cover gasket, muffler gasket, heat insulator and speed spring set

How does the carburetor size and features affect engine performance?

The P27 carburetor has a 27mm bore and a 30.5mm air intake that determines airflow and throttle response. The included upgrade copper jets give you options to fine-tune fuel delivery for better idle stability and throttle transition on varied loads.

• 27mm carburetor bore for a balance of airflow and torque delivery
• 30.5mm air intake and 52mm mounting hole spacing for correct fitment
• Built-in fuel tap simplifies draining and reduces leaks during storage
• Two jets (104#, 107#) allow richer or leaner pilot/main tuning

How do I use this kit during a maintenance session?

Remove the old carburetor and related consumables, install the new gaskets and carburetor, then fit the ignition and pull-start parts as needed. Follow your engine’s torque specs and gap settings for the spark plug and ignition coil to ensure dependable starting and running.

• Replace old gaskets and seals to stop vacuum and fuel leaks
• Swap in the new carburetor and try the supplied jets to balance mixture
• Install the spark plug and ignition coil; test pull-start assembly
• Use the flameout switch and heat insulator where applicable for safety

Who this kit is for: This TURBOTUNITY Carburetor Tune Up Kit is aimed at DIY mechanics, small-engine service shops, and owners of mini bikes, go-karts, water or trash pumps, log splitters, power pressure washers and air compressors that run Honda GX390-style or compatible Predator 420 engines. If you need a single boxed solution to refresh fuel, ignition and starting components for 389cc–420cc small engines (except generators), this kit supplies the common parts and tuning options to get engines back into reliable service.