Yamaha F25 [158/444] Oil pump

5-21

POWR

OIL PUMP

SERVICE POINTS

Cylinder head inspection

1. Measure:

● Cylinder head warpage

Out of specification → Resurface or

replace the cylinder head.

Warpage limit:

0.1 mm (0.004 in)

Resurfacing steps:

● Place a 400 ~ 600 grit wet sandpaper

on the surface plate.

● Resurface the cylinder head using a

figure-eight sanding pattern.

NOTE:

To ensure an even surface, rotate the cyl-

inder head several times.

Oil pump inspection

1. Measure:

● Clearances a, b, and c

Out of specification → Replace the oil

pump.

Clearance:

a: 0.12 mm max. (0.005 in max.)

b: 0.09 ~ 0.15 mm

(0.004 ~ 0.006 in)

c: 0.03 ~ 0.08 mm

(0.001 ~ 0.003 in)