Needle And Seat Pressure Test Mikuni Cv; Inlet Needle And Seat; Fuel Level (Mikuni Cv) - Polaris Magnum 2x4 Service Manual

FUEL SYSTEM/CARBURETION
Needle and Seat Pressure Test Mikuni CV
Needle and Seat Pressure Test
1. Invert the carburetor and install a Mity-Vac™ to the fuel
inlet fitting. Apply
5
PSI pressure to inlet fitting. The
needle and seat should hold pressure indefinitely. If
not, inspect needle and seat.
Inlet Needle and Seat
If foreign matter is caught between the sealing surfaces
of the needle valve seat and needle valve, or if they are
worn, the fuel will continue flowing and cause overflow.
Conversely, if the inlet needle sticks closed, the fuel will
not flow into the float chamber.
If
overflow occurs, clean
the float chamber, float parts and fuel passages, and in-
spect the needle and seat for wear or damage.
Inspect float height and pressure test needle and seat as-
sembly prior to carb installation. See page 4.37.
Fuel Level
A fuel level test can be performed on some models if the
drain hose fitting is accessible. Be sure to re-attach the
bowl drain hose after performing the test. A fuel level test
allows you to observe the height of the fuel in the float bowl
without removing the carburetor. The fuel level can be ob-
served with the engine either running or shut off, however,
engine must run briefly to allow fuel level to stabilize. Be
sure to review all fuel warnings on page 4.41 and 4.44.
1. Attach
a
clear line to drain fitting. Be sure line fits tightly
on fitting. Position hose along side of carburetor as
shown.
2. Open bowl drain screw by turning counterclockwise
approximately two turns. Start and run engine for 3 to 5
seconds to allow fuel level to stabilize in the line. If level
is out of specification, remove carburetor and inspect
inlet needle and seat, float height, passages, etc.
5/98
4.40
Fuel Level
1.5 mm
.060"
\
Bowl Mating
Surface
Polaris Industries Inc.