Products Description
GX390 Piston Assembly Kit | 13HP 4-Stroke Engine Replacement for Water Pump
Complete Piston Assy with Rings, Wrist Pin & Circlips | Standard Bore 88mm for Honda-Style 188F/190F Gasoline Engines
Water pump GX390 Piston assy
This complete GX390 piston assembly kit is engineered as a direct OEM-spec replacement for the 389cc single-cylinder 4-stroke gasoline engines powering high-pressure water pumps, open-frame generators, pressure washers, and compactors. The kit includes every component required for a full piston-and-ring overhaul: a hypereutectic aluminum-silicon alloy piston with a standard 88mm bore diameter, a hardened steel wrist pin, a three-ring set (two compression rings and one oil control ring assembly with expander), and two steel retaining circlips - all packaged in a branded retail box with a component visual guide. Compatible with Honda GX390 engines and the widely cloned 188F and 190F engine platforms rated at approximately 13HP, this assembly restores compression, oil control, and power output to engines experiencing blow-by, high oil consumption, or cold-start compression loss. For water pump service centers, generator repair workshops, and engine rebuilders serving agricultural, construction, and municipal equipment fleets, this all-in-one kit eliminates the separate sourcing of individual piston components and ensures ring-to-piston dimensional compatibility out of the box.
Technical Profiles & Materials
Case-Hardened Steel Wrist Pin：
The wrist pin is manufactured from low-carbon alloy steel, carburized and hardened to produce a surface layer of HRC 58–62 over a tough, ductile core. This case-hardening profile provides the wear resistance required at the pin-to-piston and pin-to-connecting-rod small-end bearing interfaces while maintaining the impact toughness needed to absorb the cyclic loading peaks that occur during each combustion event. The pin is finished to a surface roughness of Ra ≤ 0.2µm, ensuring smooth articulation within the piston pin bore without galling.
Complete Kit Format with Branded Retail Packaging ：
All components are supplied in a single branded box labeled "GX390 PISTON ASSEMBLY" with a visual icon guide identifying each included part, enabling quick workshop inventory verification without opening the packaging. The piston is individually wrapped to protect the skirt coating and ring-groove surfaces during transit. The ring set, wrist pin, and circlips are sealed in separate inner bags to prevent mixed-part confusion and surface damage from component-to-component contact during shipping.
Technical Specifications
| ITEM | DETAILS |
| Type | Complete Piston Assembly Kit - Standard Bore |
| Application | 4-Stroke Gasoline Engine - GX390 / 188F / 190F Water Pump, Generator, Pressure Washer, Compactor |
| Code | 1604007 |
| Material | Hypereutectic Al-Si Alloy Piston (Graphite-Coated Skirt), Chrome-Plated Compression Ring, Case-Hardened Steel Wrist Pin, Steel Circlips |
| Details explanation | Bore: 88mm Standard · Engine: 389cc, 13HP, Single-Cylinder 4-Stroke · Piston Material: Hypereutectic Al-Si (Si 11–13%), Graphite/MoS₂ Skirt Coating · Ring Set: 1× Chrome-Plated Barrel-Faced Top Ring, 1× Taper-Faced 2nd Ring, 1× 3-Piece Oil Control Ring · Wrist Pin: Case-Hardened Steel, Surface HRC 58–62, Ra ≤0.2µm, |
| Brand Name | SeaSummer |
| Operating Temp | -20°C to +200°C Piston Crown Service Range |
| Delivery Time | 30 Days |
| Packaging | Cardboard packaging |
Products Application
Engine Rebuilder & Aftermarket Parts Supply
Independent engine rebuilders and aftermarket parts distributors serving the global installed base of Honda GX390-based equipment - among the most cloned industrial engines worldwide - rely on this complete piston kit as a catalog staple. The all-in-one format (piston + rings + pin + circlips) increases average order value per rebuild compared to selling components separately, while the branded retail packaging with visual contents guide reduces customer misidentification and returns. For online B2B and B2C parts retailers, the GX390 platform's massive search volume - driven by water pump, generator, and pressure washer owners seeking engine parts - makes this piston assembly a consistently high-traffic listing with strong cross-sale potential for gaskets.
Generator Engine Compression Restoration
Portable and standby generators powered by GX390-clone engines in the 10–13HP range develop piston-ring-related blow-by after extended service, particularly when operated in dusty environments where air filtration maintenance has been inconsistent. The resulting blow-by pressurizes the crankcase, forces oil past seals, and reduces fuel efficiency at the generator's governed speed. Installing this complete piston assembly - with its chrome-plated top ring and three-piece oil ring - restores both compression and oil control in a single teardown, returning the generator to reliable cold-starting and rated power output for the next service interval. The kit's standard 88mm bore dimension eliminates the need to measure and order oversize pistons for engines that have not exceeded factory bore wear limits.
Water Pump Engine Overhaul & Rebuild
High-pressure water pumps in irrigation, flood control, and construction dewatering service accumulate heavy runtime hours under continuous full-throttle operation, leading to progressive compression loss as piston rings wear and cylinder sealing degrades. This GX390 piston assembly kit is the core of a standard in-frame overhaul, restoring compression pressure to factory specification when paired with a cylinder hone and new gasket set. Pump service centers serving agricultural cooperatives and municipal water authorities stock this kit as a high-demand overhaul consumable, enabling same-day engine rebuild turnaround during critical irrigation and drainage seasons without waiting for individual component deliveries.
Quality and Craftsmanship Details
Products Package
About Us
As a premier garden machinery parts supplier, Jiaxing Norsun Trading Co., Ltd. bridges global distributors with over 100 vetted China manufacturers. We streamline your B2B supply chain through strict quality control, flexible production, and factory-direct wholesale pricing. Partner with us for reliable, high-volume sourcing of precision-engineered outdoor power equipment components.
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YOUR PROFESSIONAL ONE-STOP SOURCE
FOR 10000+ OUALITY PARTS
Verified Factory Excellence
BACKED BY 200+ TRUSTED FACTORY PARTNERS
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FAQ
Q: Are you an impartial industrial components dealer or a direct China water pump factors factory?
A:We are a direct, ISO9001-certified engineering water pump components manufacturing facility and precision fluid-control factor manufacture exporter primarily based in China. We function our personal cleanroom injection molding bays, computerized ultrasonic welding arrays, computerized hydraulic stress check stations, and clean-room packaging lines, passing direct-factory wholesale price financial savings straight to your element procurement margins.
Q: Can your manufacturing unit furnish full certification forms for food-contact or consuming water compliance?
A: Yes, absolutely. For food, beverage, or scientific applications, our manufacturing unit makes use of one hundred percent virgin, un-recycled polypropylene resins accompanied by means of fabric traceability certificates. We mechanically furnish B2B purchasers with complete FDA compliance documentation, NSF-grade compound declarations, and RoHS/REACH chemical protection screening sheets to make certain clean clearance thru worldwide customs.
Q: Do you provide customization picks for distinctly corrosive fluids like sturdy acids or ozone?
A: Yes, we are a thoroughly succesful OEM/ODM supplier. For aggressive chemical or ozone environments, we can improve the 12x26.5mm valve configuration in our factory: substituting the general PP housing with top class PVDF (Fluoropolymer) and changing any steel springs with Hastelloy or whole springless gravity-ball architecture, making sure final chemical resistance.
Q: How do we impervious a pattern batch to execute computerized lifecycle and burst-pressure testing?
A: We relatively inspire complete laboratory contrast earlier than logging mass grant agreements. We can ship a pattern lot of 5-10 gadgets of our inventory 12x26.5mm take a look at valves for assessment (setup costs and DHL/FedEx air freight apply). Once the factors pass by your inner lifecycle verification and a formal wholesale quantity manufacturing contract or container run is locked in, the sampling charges are a hundred percent credited returned to your industrial balance.
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