4
100
ENGINE POWER OUTPUT LOW
Step
Action
Yes
No
1
Perform OBD System Check.
Are any DTCs found?
Go to applicable DTC Table.
Go to step 2.
2
Perform a careful visual check.
Is a problem found?
Repair
Go to step 3.
3
Check the following fuel system components for dirt, water, or
other contaminants.
• Fuel tanks
• Fuel filter
• Fuel lines
• Fuel pumps
Is a problem found?
Repair
Go to step 4.
4
Verify that fuel pressure is 38-43 psi (262-296 kPa). See
CHECK/
RELIEVE FUEL SYSTEM PRESSURE
in
SECTION 5 -
REMOVAL/INSTALLATION
.
Is a problem found?
Repair
Go to step 5.
5
Verify crankcase oil is at the correct level.
Is a problem found?
Add crankcase oil.
Go to step 6.
6
Verify air filter element is clean and dry.
Is a problem found?
Replace air filter element.
Go to step 7.
7
Verify engine is not supporting a greater load than intended for its
application? Check for the following:
• Damaged drive belt.
• For mowers, verify blades are not restricted by debris.
• Faulty pulley bearing(s).
Is a problem found?
Repair
Go to step 8.
8
Verify spark plugs are:
• Gapped properly.
• Not gas fouled.
• Not excessively worn.
Is a problem found?
Repair
Go to step 9.
9
Verify exhaust is not restricted.
Is a problem found?
Repair
Go to step 10.
Continued...
Not for
Reproduction
Summary of Contents for VANGUARD M490000
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