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Copyright © 2005 ICS, Blount Inc.
633GC SHOP MANUAL
D Plug one end of the main fuel pick-up
tube.
E Re-pressurize the tube to 7 psi
(0.5 bar).
F Replace the tube if pressure is not
maintained.
G If the main fuel pick-up tube does
maintain pressure, than the leak
has been isolated to the carburetor.
Refer to the Walbro Diaphragm
Carburetor Service Manual.
26.3 The fuel tank breather stabilizes the
pressure in the fuel tank preventing
both excessive pressure, which
could flood the engine, and negative
pressure, which could starve the
engine of fuel.
26.4 Testing the fuel tank breather.
A Attach the pressure gauge and bulb
to the fuel tank plug. Plug the fuel line
at the carburetor end. Pressurize the
tube to 4.5 psi (0.3 bar).
B The pressure should reduce to nearly
0 psi (0 bar) over about 3 seconds.
26. FUEL SYSTEM LEAKS
