Cylinder / Piston / Piston Ring - BRP Johnson 4HP Service Manual

POWERHEAD

CYLINDER / PISTON / PISTON RING

CYLINDER / PISTON / PISTON RING
Cylinder distortion
Using a straightedge and the thickness gauge, measure the
gasket surface of the cylinder at a total of six locations as
shown in the figure.

Thickness gauge
Cylinder distortion:
Service limit: 0.05 mm (0.002 in)
If the measurement exceeds the service limit, resurface or
replace the cylinder.
NOTE:
The cylinder can be resurfaced, using a surface plate and a
#400 grit wet sandpaper.
Move the cylinder in a figure eight pattern when sanding.
Water jacket
Inspect the water jackets for clog or obstruction. Clean the
water jackets if necessary.
Cylinder bore
Inspect the cylinder wall for scratches, roughness or ridges
which indicate excessive wear.
If the cylinder bore is very rough or deeply scratched or
ridged, rebore the cylinder and use an oversize piston.
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