Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Anti-Backfire Gulp Valve




1. Disconnect the air supply hose from the air pump side of the valve (Fig. 1).

2. Observe the valve pintle by looking inside the valve through the disconnected port. Accelerate the engine to approximately 3000 rpm, suddenly release the throttle, the pintle should be open and then close.