Description

This piston kit is designed for supercharged Sea-Doo Rotax 1503 4-TEC engines, available in standard size (STD) or oversized (+0.5mm). It corresponds to OEM part number 420890244 and includes the piston along with its ring set (top ring, sealing ring, and oil control ring) and assembly accessories. The assembly ensures compression in the combustion chamber, controls oil consumption, and facilitates thermal transfer to the cylinder sleeve. It is used for preventive maintenance during engine overhauls or cylinder honing, as well as for replacement following a loss of compression, overheating, or engine failure.

Technical Specifications

OEM Reference: 420890244
Manufacturer Reference: 4-TEC piston kit STD (big bore)
Type: Complete piston kit with rings, standard size
Condition: New
Packaging: 1 kit for 3 cylinders (pistons, rings, wrist pins, circlips)
Weight: 650 g
Regulated substances: none
Installation: engine assembly by a qualified mechanic, observe end gap and ring positioning

Compatibility

This piston kit is compatible with Sea-Doo personal watercraft equipped with the Rotax 1503 4-TEC engine in 215, 255, and 260 hp versions, produced between 2007 and 2018:

2007: GTX 155 Wake, GTX 215 Wake
2008: GTX 215, GTX 215 Limited, GTX 215 Wake
2009: GTX 215, GTX 255 Limited iS
2010: GTX 215 iS
2011: GTX 215, GTX 215 iS
2012: GTR 215, GTX 215
2013: GTR 215, GTX 215
2014: GTR 215, GTX 215 Limited, GTX 260 Limited iS
2015: GTR 215, GTX 215 Limited, GTX 260 Limited iS
Also the RXP and RXT models equipped with the 1503 4-TEC 215/255/260 hp engine

Also compatible with Williams Tender boats equipped with the Rotax 1503 engine:

Williams 435 Sportjet (Rotax ACE 1503)
Williams 400 Sportjet
Williams 460 Sportjet
Williams 520 Sportjet

⚠️ Always check your serial number (VIN) and original OEM reference before ordering to confirm exact compatibility with your model.

Why Replace the Piston Kit?

The piston and its rings work constantly at very high temperatures and under high pressure. Over hours of operation, the piston becomes scored and the rings lose their tension, become clogged with carbon deposits, or break, which leads to a drop in compression, abnormal oil consumption, and eventually, scoring of the cylinder sleeve, which can destroy the engine.

Decreased power or top speed
Hard starting and irregular compression between cylinders
Blue smoke from the exhaust
Increased oil consumption
Unusual engine noise or knocking

It is recommended to replace the piston kit whenever the engine is opened, at the beginning of the season, or after approximately 50 hours of intensive navigation, in order to maintain compression and the lifespan of your Sea-Doo.