Mercury 40 Service Manual page 228

CYLINDER HEAD
Valve Springs
Check free length limit of each spring. Replace valve springs if not in specification.
Check each spring on a flat surface using a square. Rotate spring and check space between
the top coil and square. Replace valve springs if not in specification.
Page 4A-32
Valve Spring Free Length
1.569 - 1.491 in. (39.85 – 37.85 mm)
a
55797
Valve Spring Tilt Specification "a"
Less than 0.06 in. (1.7 mm)
55846
90-828631R3 MARCH 1999