Chapter 8: Exhaust
80
3. Clean the cylinder head and muffler of any resid-
ual gasket material.
4. Using a new gasket, install the muffler by follow-
ing the above steps in reverse order.
NOTE: Tighten the muffler nuts to a torque of 84
in-lbs (10Nm).
5. Test run the engine before returning to service.
Catalytic converter muffler
The CARB (California) compliant engines use a cata-
lytic converter muffler. This muffler also has an air
injector to help with the catalytic reaction in the muffler.
The Catalytic muffler can be identified by the presence
of this air injector. See Figure 8.4.
NOTE: The catalytic converter muffler is
removed/replaced by following the same proce-
dures as the conventional muffler.
The catalytic converter is most efficient when it
receives the exhaust of an engine running slightly
above the stoichiometric point. The catalytic converter
breaks down the exhaust, through chemical reactions,
to reduce the nitrogen oxide, carbon monoxide and the
hydrocarbon emissions. The air injector adds oxygen
to the converter so that it can complete its chemical
reaction inside the muffler.
NOTE: Stoichiometric point is defined as the
point where the mass ratio of fuel to air is chemi-
cally balanced. For gasoline, the stoichiometric
point is approximately 14.7 to 1.
Figure 8.4
Air injector
www.mymowerparts.com
For Discount White Outdoor Parts Call 606-678-9623 or 606-561-4983
To Next Page
Loading...
Need help?
General
