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)

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Engine Knocks


1. Check ignition timing. If timing is too advanced, adjust as necessary. If timing is satisfactory, proceed to step 2.
2. Inspect spark plug. If plug is running too hot, install colder type spark plug. If plug is satisfactory, proceed to step 3.
3. Inspect distributor. If governor spring is unhooked or broken, repair or replace. If pin hole in governor is worn, replace governor.