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

Compression Check

The maximum allowable compression pressure difference between any two cylinders is 100 kPa (15 psi).

Measure the highest pressure reading on the compression gauge.

The standard compression pressure is 1,300 kPa (218 psi).
The minimum allowable compression pressure is 1,000 kPa (145 psi)