WhichPartFits.com

Small Engine

Honda GX630

4-Stroke

The Honda GX630 is a 688cc V-twin 4-stroke overhead-valve engine built for commercial and industrial equipment that demands high torque — large generators, riding mowers, welders, and heavy-duty power equipment. Unlike Honda's single-cylinder GX engines, the GX630 uses a V-twin configuration for smoother power delivery and reduced vibration under load. It uses a Keihin carburetor and accepts NGK BPR6ES or Champion RC12YC spark plugs. Oil change intervals every 100 hours and air filter maintenance every 50 hours are standard. Valve clearance should be inspected every 300 hours.

Verify before ordering: Fitment can vary by serial number, production date, region, and sub-model. Match the OEM number and physical dimensions before ordering.

Honda GX630 quick specs

Equipment
Small Engine · 4-Stroke
Covered Parts
Spark Plug, Air Filter, Oil Filter, Fuel Filter, Carburetor
OEM References
98079-5587G, 17210-Z6L-010, 15400-PLM-A02, 16910-Z6L-003, 16100-Z9E-033
Model Family
GX630, GX660, GX690
Data Confidence
Not yet independently reviewed

Quick Fitment

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Tune-Up Kit

Common service bundle: spark plug, air filter, fuel filter, carburetor.

Maintenance Interval

Inspect filters and fuel lines each season, replace spark plugs during annual service, and service carb/fuel-system parts when starting or idle symptoms appear.

Before You Buy

  • Confirm the full model is Honda GX630, not just the family name.
  • Check serial number, production date, and regional variant before ordering.
  • Match the old OEM number stamped on the removed part when available.
  • Compare dimensions, plug gap, thread, fuel line diameter, or chain pitch/gauge where applicable.

Common Mistakes

  • Ordering from a family listing without checking the exact sub-model.
  • Buying a kit that includes the headline part but wrong gaskets, lines, or bulb size.
  • Choosing the wrong carburetor revision when multiple versions were used.
  • Installing the correct plug number with the wrong gap.

Symptoms Map

Won't start

Spark plug, fuel filter, primer bulb, carburetor

Starts then dies

Fuel filter, fuel line kit, carburetor

Bogs under throttle

Air filter, carburetor, spark plug gap

Replacement Options

Best OEM equivalent

Start with OEM references 98079-5587G, 17210-Z6L-010, 15400-PLM-A02, 16910-Z6L-003 and match the removed part before choosing a listing.

Named part options

Cross-check named parts such as NGK ZFR5F (spark plug), Stens 100-005 (air filter), Stens 120-722 (oil filter) against the OEM number, identity label, and dimensions.

Best for annual tune-up

Bundle spark plug, air filter, fuel filter when servicing the Honda GX630 at the start of the season.

Best if replacing fuel system

Compare the fuel filter, carburetor together so line routing, bulb size, filter style, and carburetor connections match.

Best budget kit

Use kit listings only when every included part matches this model page; cheap kits often mix correct headline parts with wrong bulbs, lines, or gaskets.

FAQ

Should I buy OEM or aftermarket parts for the Honda GX630? Use OEM when the part controls fuel metering, ignition, or safety. Aftermarket kits can be useful for routine filters, bulbs, plugs, and tune-up bundles when the OEM number and dimensions match.

How do I avoid ordering the wrong carburetor for the GX630? Match the carburetor number stamped on the removed unit, then compare linkage, choke setup, primer routing, gasket stack, and fuel-inlet direction.

What should I check before replacing fuel-system parts? Photograph the old fuel-line routing, match line diameter and filter style, and compare primer bulb size before buying a kit.

As an Amazon Associate, WhichPartFits earns from qualifying purchases. Match the OEM number, dimensions, and model variant before buying.

Spark Plug

OEM98079-5587G
Dimensions
0.7-0.8mm gap
Variant notes
NGK ZFR5F equivalent; V-twin engine requires one plug per cylinder (2 total)

Air Filter

OEM17210-Z6L-010
Variant notes
Also fits GX660, GX690, GX630R, GX630RH

Oil Filter

OEM15400-PLM-A02
Variant notes
Also fits GX610, GX620, GX660, GX670, GX690

Fuel Filter

OEM16910-Z6L-003
Variant notes
Inline fuel filter; also fits GX660, GX690, GXV630

Carburetor

OEM16100-Z9E-033
Variant notes
Also supersedes 16100-Z9E-023 and 16100-Z9E-003; fits GX630, GX660, GX690 V-twin engines