Intake Valve Yanmar 105225-11100

Function and technical context

The intake valve is part of the valve train of the cylinder head and is responsible for regulating the entry of the air-fuel mixture into the combustion chamber at the precise moment of the four-stroke cycle. It works within the timing system of the marine diesel engine, coordinating with the camshaft, springs and valve seats to ensure optimal cylinder filling. In GM series Yanmar engines, where three units are mounted per block, wear or loss of tightness of any of these valves causes a direct drop in compression of the affected cylinder, which translates into loss of power, difficult starting and irregular combustion. Reference 105225-11100 corresponds to callout 6 of section 16 (Cylinder Head) of the official Yanmar breakdown.

When to replace this part?

The most common symptoms of a deteriorated intake valve include loss of compression measured in the cylinder test, high fuel consumption, bluish or black smoke from the exhaust, irregular vibrations at idle and difficulty reaching the working rpm. In intensive use marine engines, it is recommended to inspect the condition of the valves—play, seat and stem wear—during each cylinder head rectification or deep inspection, usually every 1,000-1,500 hours of operation or when the compression drops below the values ​​specified by Yanmar. Replacing the intake valves preventively when rectifying the cylinder head avoids having to repeat the disassembly of the engine in the middle of the navigation season.