Mercury Jet 40 - Worn;Dull Impeller; Impeller Clearance Adjustment

MAINTENANCE
45
ob01657
a
a - Exhaust fins
Worn/Dull Impeller
The intake of gravel through the pump can round off and wear the leading edges of the impeller. Some conditions
that could be experienced from a worn/dull impeller are as follows:
• Noticeable performance loss, especially on acceleration
• Difficulty getting the boat on plane
• An increase in engine RPM at wide open throttle
IMPORTANT: Do not sharpen or alter the top side lifting angle.
Check the impeller blades occasionally for damage. Use a flat file to resharpen the leading edges. Sharpen to a
0.8 mm (1/32 in.) radius by removing material from bottom side only.
ob01409
b
a
a - Leading edge b - Top side lifting angle
Impeller Clearance Adjustment
The impeller should be adjusted so there is approximately 0.8 mm (0.03 in.) clearance between the impeller edge
and liner. Operating the jet drive in waters that contain sand and gravel can cause wear to the impeller blades,
and the clearance will start to exceed 0.8 mm (0.03 in.).