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If the starter is not assembled to the engine you can connect a carburetor testing
gauge to the impulse hose when you perform a crankcase pressure and vacuum
test.
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The needle on the carburetor gauge should move as pressure and vacuum are
applied to the crankcase.
If the impulse line becomes blocked, the running behavior of the engine will indicate
carburetor problems, when in fact there may be none.
Carburetors
Inspect carburetor visually.
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Before testing or disassembly, visually inspect the carburetor for damage.
If something on the carburetor is physically broken or worn, most likely the
carburetor will need replacing and no further time will be spent on evaluation.
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If the carburetor has no physical damage and the throttle shaft is tight, then perform
a three step evaluation with a carburetor pressure tester, such as a ZAMA ZPG-1.
This will allow any internal faults in the carburetor to be identified quickly.
Fuel Leak Indicated by
Dirt Build-up
Worn Throttle Shaft
Worn Mounting Surface
Three step evaluation for a 4-MIX® engine used on shafted products.