Generac Power Systems GN190H, Руководство по обслуживанию и ремонту

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CRANKSHAFT SLEEVE BEARING:
The crankshaft bore in the crankcase is a pressure lubricated
oil bearing that may or may not include an additional sleeve
bearing, depending on the vintage of the engine (Figure 11.6).
The crankshaft bore in the crankcase cover is also a pres-
sure lubricated oil bearing.
Inspect the bearing and bearing bore as follows:
1. Where applicable, check the sleeve bearing in the crankcase
for damage.
a. Measure the inside diameter of the sleeve bearing.
Replace the bearing if it is worn excessively.
b. Press out the old bearing and press a new bearing into
place.
NOTE: Alignment of the oil holes in the sleeve bearing
and bearing bore in the crankcase is critical.
CRANKSHAFT SLEEVE BEARING DIAMETER
DESIGN DIAMETER = 1.104-1.106 inch
(28.044-28.099mm)
2. Inspect the crankshaft bearing bore in the crankcase cover
for damage and wear (Figure 11.7).
a. Measure the Inside diameter of the bearing bore.
b. If the bore is worn excessively, replace the crankcase
cover.
CRANKCASE BEARING BORE
IN CRANKCASE COVER
DESIGN DIAMETER = 1.103-1.105 inch
(28.030-28.058mm)
Figure 11.6 — Crankshaft Sleeve Bearing
Figure 11.7 — Bearing Bore in Crankcase Cover
COMPRESSION RELEASE
A mechanical compression release is provided on the
camshaft (Figure 11.8). A flyweight pivots on a pin mounted
in the camshaft gear. The pin itself has a cam action. When
the engine is not running, the pin holds the tappet up just
slightly, which in turn holds the exhaust valve slightly open.
This relieves compression for easier cranking.
When the camshaft spins, the flyweight moves, causing the
pin to turn. The tappet is then free to move normally.
Figure 11.8 — Compression Release Mechanism
Measure the amount of compression relief lift at the tappet
(see Figure 11.9).
BEARING
BORE
CRANKCASE
COVER
OIL SEAL
SLEEVE
BEARING
SECTION 11: CRANKSHAFT AND CAMSHAFT
44
GENER
A
C