Cub Cadet MTD 70 Series - Manual (Page 49)

F UEL S YSTEM AND G OVERNOR
43
7. Lift the shroud enough to gain access to the charcoal
canister.
8. Disconnect the fuel tank vacuum line from the canis-
ter.
9. slide the tank out of the shroud.
10. Install the fuel tank by following the previous step in
reverse order.
Evaporative (EVAP) emissions system
Gasoline is made from the graduated distillation of crude oil. It consists of a multitude of individual hydrocarbons and
has a boiling range of 86 - 410
o
F (30-210
o
C)
1
. The large quantity of hydrocarbons and the low boiling range makes
gasoline an ideal fuel for spark ignited, internal combustion engines. However, the hydrocarbons are not good for the
environment. To reduce or eliminate the release of fuel vapors into the atmosphere, an evaporative (EVAP) emis-
sions system is used. Starting with the 2008 season, an EVAP system has been offered in areas that require it. MTD
has three systems that can be used:
• Charcoal canister fuel caps.
• Charcoal canister system with the canister snapped into the tank.
• Charcoal canister system with the canister snapped into the shroud.
NOTE: All fuel caps must be tethered to the fuel tank as part of the EPA tier III emissions. A broken tether on
the fuel cap must be repaired before the unit can be put back into service.
Charcoal canister fuel caps
The simplest and most common EVAP system used on
an MTD engine is the charcoal canister fuel cap. The fuel
cap has charcoal that will grab most of the vapors that try
to escape through the vent.
When the engine is running and the fuel level drops, a
vacuum is created. The clean air that is drawn in through
the vent will pull the vapors out of the charcoal, refreshing
it for the next cycle.
A charcoal canister fuel cap can be identified by its
height. See Figure 4.14.
1. Dr. Ullmann, J, Fuels, Automotive Handbook, seventh edition. Bosch, Robert distributed by SAE Society of
Automotive Engineers, 2007. 320.
Figure 4.13
Charcoal canister
Figure 4.14
Charcoal canister fuel cap