Cub Cadet MTD 70 Series - Manual (Page 72)

61/65/70/75 Series Horizontal Shaft Engines
66
Lubrication system
MTD uses a splash lube system for it’s horizontal shaft
engines. The connecting rod has a dipper on it that
“splashes” oil around the inside of the engine. See Figure
5.6.
NOTE: The cam and tappets were removed for bet-
ter visualization of the lubrication system.
The splashing action will also atomize or change the
oil into a mist. There are two oil passages that run along
the engine cylinder. The one on the top side of the engine
is the oil supply passage. The oil mist will flow through this
passage to the cylinder head. See Figure 5.7.
The second oil passage runs along the bottom side of
the cylinder. This is the oil return passage. As the name
implies, it allows the oil collecting in the cylinder head to
return to the sump. The return passage is the tiny hole that
is in between the two tappet passages.
NOTE: Because these engines use splash lubrica-
tion, the type of oil and the oil level is critical
for proper operation of the engine. If the oil
level is too low, the dipper on the connecting rod cannot splash the oil into the engine. If the oil level is
too high, the oil will not change into a mist to reach the upper side of the engine.
Dipper
Figure 5.6
Figure 5.7
Oil supply passage
Oil return
Tappets