Piston Assembly Kit – Fits Mercury/Mariner 2.5L & Sea-Doo 2500 (Replaces 785-9737T9)

$93.49 $149.00

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Product Details

This Piston Assembly Kit serves as a direct-fit replacement for port-side cylinders on a wide range of Mercury/Mariner 2.5L V6 engines (1992–2005) and Sea-Doo 2500 series watercraft (2000–2005). Engineered to meet original equipment specifications, it ensures reliable performance and compatibility.

It directly interchanges with Mercury part numbers 785-9737T9 and 883062T3, as well as aftermarket references like RAREELECTRICAL 100-20PK and ProV 2500PV.

Installation Type: Top Guided
Bore Size: Standard (3.500/3.501 inches)
Package Contents: Complete Piston Assembly

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Mercury	785-9737T9
Mercury	883062T3
RAREELECTRICAL	100-20PK
ProV	2500PV

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Fits various 2.5L V6 outboards from Mercury and Mariner, including V-135, V-150, V-175, V-200, and associated jet drive models manufactured between 1992 and 2005. Check your engine's serial number against the listed ranges.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	V-135	135	2-Stroke	1992–1999	785-9737T9	Serial: 0G960500-0T178499
Mercury	V-140 International	140	2-Stroke	1999–2001	785-9737T9	Serial: 0T178500-1B226999
Mercury	V-150	150	2-Stroke	1992–2001	785-9737T9	Serial: 0G960500-1B226999
Mercury	V-150 EFI	150	2-Stroke	1992–2000	785-9737T9	Serial: 0G960500-0T408999
Mercury	V-175 EFI	175	2-Stroke	1992–2000	785-9737T9	Serial: 0G960500-0T408999
Mercury	V-200	200	2-Stroke	1992–2001	785-9737T9	Serial: 0G960500-1B226999
Mercury	V-200 EFI	200	2-Stroke	1992–2000	785-9737T9	Serial: 0G960500-0T408999
Mercury	XR-6	150	2-Stroke	1992–2001	785-9737T9	Serial: 0G960500-1B226999
Mercury	MAGNUM III	150	2-Stroke	1992–2001	785-9737T9	Serial: 0G960500-1B226999
Mercury	140 JET	140	2-Stroke	1992–1999	785-9737T9	Serial: 0G960500-0T178499
Mercury	200 EFI PRO MAX/SUPER MAG	200	2-Stroke	1992	785-9737T9	Serial: 0G857000-0G858150
Mercury	175XR2 JET DRIVE	175	2-Stroke	1992–2001	785-9737T9	Powerhead & Pump Applications
Mercury	210 CARB JET DRIVE	210	2-Stroke	1992–2001	785-9737T9	Powerhead & Pump Applications
Mercury	210 CARB M2 JET DRIVE	210	2-Stroke	1992–2000	785-9737T9	Powerhead & Pump Applications

Also compatible with Sea-Doo jet boats and watercraft equipped with the 2500 series engine from 2000–2005, including Challenger, Islandia, and Speedster models.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Sea-Doo	Challenger 210	210	2-Stroke	2000–2004	785-9737T9	2500 Engine
Sea-Doo	Challenger 240 EFI	240	2-Stroke	2000–2004	785-9737T9	2500 Engine
Sea-Doo	Islandia 240	240	2-Stroke	2000–2004	785-9737T9	2500 Engine
Sea-Doo	Speedster 210	210	2-Stroke	2000	785-9737T9	2500 Engine
Sea-Doo	Speedster 240	240	2-Stroke	2000–2004	785-9737T9	2500 Engine
Sea-Doo	Sportster 210	210	2-Stroke	2000	785-9737T9	2500 Engine
Sea-Doo	Utopia 210	210	2-Stroke	2001–2002	785-9737T9	2500 Engine
Sea-Doo	Utopia 240 EFI	240	2-Stroke	2001–2005	785-9737T9	2500 Engine
Sea-Doo	X-20	210	2-Stroke	2002	785-9737T9	2500 Engine

Technical Specs

Product Type: Piston Assembly Kit (Port)
Installation: Top Guided
Fuel Type Compatibility: Gasoline
Housing Material: Aluminum Alloy
Bore Diameter: 3.500/3.501 inches (88.90/88.93 mm)
Size: Standard (Matches OEM Specification)
Weight: 0.67 kg (1.47 lbs)

What’s in the Box

1x Piston Assembly Kit (Complete)

Installation Notes

Disconnect the battery and ensure the engine is cool. Drain engine oil and coolant.
Remove the cylinder head cover and cylinder head, carefully following the manufacturer's torque sequence in reverse.
Rotate the crankshaft to access the connecting rod bolts for the target piston. Remove the bolts and rod cap.
From the top of the cylinder, carefully push the old piston and rod assembly out.
Clean the cylinder bore, piston-mating surfaces, and surrounding areas of carbon and gasket residue.
Install the new piston assembly, ensuring rings are correctly clocked and using a ring compressor.
Re-install the connecting rod cap to the specified torque and reassemble the engine in reverse order.
Refill engine fluids, reconnect the battery, and perform a leak check before starting the engine.

Troubleshooting & FAQ

How can I confirm this piston fits my specific engine?

This is a port-side piston for Mercury/Mariner 2.5L V6 engines and Sea-Doo 2500 models. The most reliable way to confirm fitment is by matching your engine's model, year, and serial number to our compatibility tables. Verifying against the OEM part number (785-9737T9) is also highly recommended.

What are common signs of a failing piston?

Symptoms of a worn or damaged piston include loss of compression, excessive oil consumption, blue smoke from the exhaust, and a knocking or rattling sound from within the engine.

Is this for the Port or Starboard side?

This is a port-side piston assembly. Starboard pistons typically have a different part number and are not interchangeable.

What is the recommended engine break-in procedure after installation?

Follow your engine manufacturer’s recommended break-in procedure. Generally, this involves running the engine at varied, low-to-mid RPMs for several hours, avoiding both constant speeds and full throttle to allow the new rings to seat properly against the cylinder wall.

Is this a standard or oversized piston?

This is a standard bore (3.500/3.501 inches) piston kit, built to original OEM specifications. It is not an oversized piston for bored-out cylinders.

Do I need any special tools for this installation?

Yes, professional installation is recommended. Specialized tools such as a piston ring compressor, a torque wrench, and feeler gauges are required for proper installation and to prevent damage to the new components.

What’s the difference between an OEM part and a Sea Sierra aftermarket part?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

How fast do you ship and what does it cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

What is the warranty and return policy?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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