Generac Power Systems 941-2, 940-2 service manual Oil Sump, Oil Filter Support, Breather Assembly

Section 5.1

ENGINE OIL SYSTEM

The breather serves to maintain a partial vacuum in the engine crankcase, to prevent oil from being forced past oil seals, gaskets or rings.

See Figure 6. A reed type breather valve permits excess pressure to be vented out of the crankcase and to atmosphere through a breather tube. A breather retainer limits the movement of the breather valve. Two small oil return holes in the breather cup allow condensed oil vapors to drain back to the crankcase. A "steel wool" type breather separator separates the breather cup from the breather cover and breather tube opening.

Figure 6. Breather Assembly

INSPECTION:

Remove the breather hose. Inspect it for cracks, dam- age, hardening. Replace, if necessary.

Clean the breather cover and breather cup in com- mercial solvent. Check that the two small drain holes in the breather cup are open; open with a length of wire, if necessary.

Inspect the rivets that retain the reed type breather valve, make sure they are tight. Also check that the valve seats flat on the breather cup around the entire surface of the valve.

OIL SUMP

DESCRIPTION:

The die cast aluminum oil sump is retained to the crankcase with six (6) flanged head bolts. Install a new gasket between the oil sump and crankcase each time the oil sump is removed.

Bores are provided in the oil sump for (a) oil pump rotors and camshaft, (b) crankshaft, (c) governor gear assembly, (d) oil pickup. Cored oil passages are pro- vided from the pickup to the pump and from the pump to the crankshaft bore.

INSPECTION:

Clean the oil sump and blow dry with compressed air. Use compressed air to blow out all oil passages. Inspect the sump for cracks, damage, etc. Check the following bores in the oil sump for wear:

CRANKSHAFT BEARING BORE DIAMETER

GV-220 ENGINE

DESIGN DIAMETER: 1.104-1.105 inch (28.040-28.065mm) WEAR LIMIT: 1.106 inch (28.092mm) Maximum

CAMSHAFT BEARING BORE DIAMETER

GV-220 ENGINE

DESIGN DIAMETER: 1.299-1.300 inch (33.00-33.03mm)

WEAR LIMIT: 1.302 inch (33.06mm) Maximum

OIL PUMP INNER ROTOR SHAFT DIAMETER

GV-220 ENGINE

DESIGN DIAMETER: 0.353-0.354 inch (8.969-8.987mm)

WEAR LIMIT: 0.352 inch (8.949mm) Minimum

OIL FILTER SUPPORT

An oil filter support and its gasket are retained to the oil sump by four (4) M6-1.00 bolt.

A threaded bore is provided in the support for a low oil pressure switch. This switch will protect the engine against damaging low oil pressure by shutting the engine down automatically if oil pressure should drop below a pre-set low limit.

A high oil temperature switch is retained to the sup- port by two (2) M5 screws and lockwashers. This thermal sensor will protect the engine against damag- ing high temperature conditions through automatic shutdown.

Figure 7. Oil Filter Support

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