Vacuum Fuel Valve

Fuel Delivery Check

Fuel System Check

Engine will not start

 Four stroke engine troubleshoot

These fuel valves are operated by negative pressure produced by the intake manifold or carburetor.
Valves may be attached to the fuel tank or in line.
The valves are used as auto petcock ( fuel should not pass through valve when engine is not running).

Problems
Leaking vacuum supply line
Clogged valve
Incorrect installation

Testing valve

Disconnect fuel line to carburetor
If fuel continues to flow valve is bad or not installed properly, this will cause carburetor to flood

Turn engine over
If fuel does not flow through delivery line
Check
Installation
For gummed valve
Vacuum supply
Intake manifold leak (be sure the manifold is producing a vacuum)





Scooter ATV Fuel Check Valve

Vacuum check valve

Scooter ATV
D1
ATV Fuel valve

R2
Vacuum Fuel Valve High Flow

Vacuum Fuel Valve High Flow
Type E