59
FLANGE
10
COUNTER-
BALANCE
SHAFT
LUBRICATION SYSTEMS
The lubrication system used with all Tecumseh
horizontal crankshaft engines covered in this manual
utilize a splash type system. An oil dipper on the
connecting rod splashes oil in the crankcase to
lubricate all internal moving parts. The oil dipper is
either bolted on or may be cast on to the cap with one
of the rod bolts (diag. 6).
All vertical shaft engines use a positive displacement
plunger oil pump or a rotary oil pump. Oil is pumped
from the bottom of the crankcase, up through the
camshaft and over to the top main bearing. Oil under
pressure lubricates the top crankshaft main bearing
and camshaft upper bearing (diag. 7). A crankshaft
drilling also provides oil to the crankpin journal on
engine models OHV 13.5 -16.5.
On all Tecumseh vertical shaft 4-cycle engines, the
oil is sprayed out under pressure through a small hole
between the top camshaft and crankshaft bearing to
lubricate the piston, connecting rod, and other internal
parts (diag. 5).
The plunger style oil pump is located on an eccentric
on the camshaft. As the camshaft rotates, the
eccentric moves the barrel back and forth on the
plunger forcing oil through the hole in the center of
the camshaft. The ball on the end of the plunger is
anchored in a recess in the cylinder flange (diag. 8).
The rotary pump is driven by the camshaft. It uses a
lobed gear in a rotating ring to provide positive oil
displacement (diag. 9).
CAMSHAFT
GOVERNOR
OIL DRAIN
HOLE
SPRAY
MIST HOLE
5
COUNTERBALANCE SYSTEMS
Some Tecumseh engines may be equipped with an
Ultra-Balance
®
counterbalance system. This system
uses a single weighted shaft that is driven off the
crankshaft. This shaft's function is to counteract the
imbalance caused by the counterweights on the
crankshaft (diag. 10).
A dual shaft counterbalance is also used on some
engine models. A gear on the crankshaft drives the
counterbalance with the thicker gear, which in turn
drives the second counter balance shaft. For timing
of either counterbalance system, see " Engine
Assembly Procedure " in the Service section of this
chapter.
DIPPER
6
CAMSHAFT
DRILLED
CAMSHAFT
PASSAGE
7
PLUG
BARREL TYPE
LUBRICATION
PUMP
CRANKSHAFT
OIL PASSAGE
CRANKCASE
PASSAGE
MAIN BEARING
OIL GROOVE
SPRAY
MIST HOLE
9
FLAT
ASSEMBLE PUMP HOUSING
WITH INSIDE CHAMFER
TOWARD CAMSHAFT GEAR
8
NOTE: INSTALL OIL PUMP AFTER THE SUMP IS ON
DRIVE
GEAR
www.mymowerparts.com
For Discount Tecumseh Engine Parts Call 606-678-9623 or 606-561-4983