20B Checking Spark Advance

1. Re-connect coolant sensor connector, then remove the air cleaner assembly, if necessary.
2. With tachometer and timing light connected to engine and engine at normal operating temperature, raise engine speed to 2000 RPM and check timing.
3. If timing is 19° BTDC minimum for 4-153 engines with manual transaxle or 27° BTDC minimum for other models, proceed to Test 21. 21A Fuel Supply & Return System
4. If spark advance is not within minimum specification, replace logic module.