Mechanical Diaphragm Fuel Pump For Model 490000; Volumetric Test - Briggs & Stratton VANGUARD 810 EFI Repair Manual

Section 5: Removal/Installation

Mechanical Diaphragm Fuel Pump for Model 490000

Volumetric Test

Perform a volumetric test to verify that the
proper amount of fuel is being delivered to the
engine. Proceed as follows:
1. See Safety Precautions.
2. Remove battery negative cable (black)
from battery negative (-) terminal.
3. Squeeze clip at fuel outlet port and remove
hose to fuel pump module.
NOTE: Wrap shop towel around fi tting to
catch any fuel leakage.
4. Obtain a stop watch and a graduated cylin-
der.
5. Attach suitable hose to fuel outlet port and
direct free end into graduated cylinder. See
Figure 5-26.
6. Install battery negative cable (black) to bat-
tery negative (-) terminal.
7. Start engine and watch for fuel discharge
from outlet port hose. As soon as fuel fl ow
is observed, start the stopwatch.
8. Run engine for 30 seconds at 2200 RPM.
9. After the time has elapsed, turn off the en-
gine and stop the watch.
10. Measure the volume of fuel discharged into
the graduated cylinder. See the table be-
low for the approximate amount of fuel that
should be discharged.
Pump Fuel for 30 Seconds
Approximate
Fuel Amount
237 ml
0.5 pint
0.25 quart
1.0 cup
NOTES:
• Position the fuel tank so that it is near level
with the fuel pump. Do not place the gradu-
ated cylinder BELOW the fuel pump or
gravity feed will produce false results.
• The engine will run longer than the 30 sec-
ond test interval using fuel trapped in the
fuel pump module.
• View the graduated cylinder with your eyes
directly level with the fuel. Note that the fuel
curves up the sides of the graduated cyl-
inder. This curve is called a meniscus. For
the most accurate reading, read the mea-
surement from the bottom of the meniscus.
• The volumetric measurement is only ap-
proximate. The fuel pump is likely function-
ing properly if the test results are within
10% of the approximate fuel amount.
Engine Cranks But Will Not Start
Use the starter to turn the engine over for 10
seconds. See the table below for the approxi-
mate amount of fuel that should be discharged.
Crank Engine for 10 Seconds
Approximate
Fuel Amount
133
65 ml
0.13 pint
0.06 quart
0.27 cup