Internal Engine Components | Mercury Outboard

Specifications

Yamaha Inline 4-Cylinder Application

The Advanced Sleeve 1185SA is designed for compatible Yamaha inline 4-cylinder four-stroke powerheads.

Cylinder sleeves are commonly used during a powerhead rebuild when the original cylinder wall is damaged, excessively worn, scored, corroded, or has already been machined beyond an acceptable oversize repair.

Alternate 3.310" OD Cylinder Sleeve

Advanced Sleeve 1185SC - 3.310" Outside Diameter

Alternate replacement sleeve for compatible Yamaha inline four-cylinder four-stroke powerheads.

Outside Diameter: 3.310"
Bore: 3.118"
Length: 5.195"

The 1185SC uses a .040" larger outside diameter than the 1185SA while retaining the same nominal bore and length.

View 1185SC 3.310" OD Sleeve

1185SA vs. 1185SC Cylinder Sleeve

What a Replacement Cylinder Sleeve Does

A cylinder sleeve restores the cylinder wall when the original bore cannot be reused or machined successfully. The damaged original cylinder area is machined to accept the replacement sleeve, and the sleeve is then installed and finished to the required piston bore and clearance.

Sleeving can allow an otherwise damaged engine block to be returned to service when a standard or oversize piston repair is no longer practical.

When a Cylinder Sleeve May Be Needed

• Deep cylinder-wall scoring
• Severe piston or ring damage
• Corrosion or pitting in the cylinder wall
• Previous cylinder machining beyond available piston sizes
• Excessive taper or out-of-round
• Localized cylinder-wall damage
• Restoring a damaged block during a complete powerhead rebuild

Machine Shop Installation

Cylinder sleeve installation requires precision block machining. The block should be measured before selecting the sleeve so the correct outside diameter and required interference fit can be determined.

After installation, the replacement sleeve must be bored and honed to the correct finished dimension for the piston being installed.

Parts to Inspect During a Sleeved Powerhead Rebuild

• Pistons and piston size
• Piston rings
• Cylinder bore and finished piston clearance
• Connecting rod bearings
• Connecting rod bolts
• Crankshaft main bearings
• Crankshaft journals
• Cylinder head sealing surface
• Intake and exhaust valves
• Valve stem seals
• Oil passages and lubrication system
• Powerhead gaskets and seals

Shop Yamaha Engine Rebuild Parts by Model

Need pistons, bearings, rings, valves, gaskets or other components for the same rebuild? Use Pro Marine's Yamaha Engine Rebuild Parts by Model section to locate compatible internal engine components.

Key Features and Benefits

• Advanced Sleeve aftermarket cylinder sleeve
• Part number 1185SA
• Fits compatible Yamaha inline 4-cylinder four-stroke powerheads
• 3.270" outside diameter
• 3.118" bore
• 5.195" length
• Type CS
• Designed for professional cylinder-block machining and installation
• Can restore cylinders that cannot be repaired with a normal overbore
• 1185SC larger 3.310" OD sleeve option linked above
• Yamaha rebuild parts by model linked above

FAQ

What engines does Advanced Sleeve 1185SA fit?
It is designed for compatible Yamaha inline 4-cylinder four-stroke engines. Verify block and sleeve dimensions before ordering.

What is the outside diameter of 1185SA?
The 1185SA has a 3.270" outside diameter.

What is the bore size?
The nominal bore is 3.118".

How long is the sleeve?
The sleeve length is 5.195".

What is the difference between 1185SA and 1185SC?
The key difference is the outside diameter. 1185SA is 3.270" OD, while 1185SC is 3.310" OD. Both list a 3.118" bore and 5.195" length.

Can I install a cylinder sleeve myself?
Cylinder sleeve installation requires precision machining of the engine block and final boring/honing of the installed sleeve. This work is normally performed by an experienced marine machine shop.

Does the sleeve come finished and ready for the piston?
The installed sleeve must be checked and machined to the required finished bore and piston-to-wall clearance for the piston being used.

Where can I find other Yamaha engine rebuild parts?
Use the Yamaha Engine Rebuild Parts by Model section linked above.

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