How to adjust idle on a Mercury outboard engine refers to the process of adjusting idle speed on a carburetor. Use the following information when making idle speed adjustments on your Mercury outboard engine. It should be noted, the engine must be completely warmed up before making idle speed adjustments. You cannot correctly adjust the idle in cold conditions.
Idle Speed Adjustment
- With the Mercury outboard engine in neutral gear and in the water or test tank, start the engine and allow it to warm up.
- Shift the outboard engine into forward gear.
- Starting turning the idle adjustment screw on the carburetor to attain the specified idle rpm. Refer to the download repair manual for idle rpm specifications.
- Rev the outboard engine 2 or 3 times and then allow it to idle for 15 seconds. If the engine holds a steady and stable idle rpm then no other idle adjustments are needed. If the idle is unstable, then carburetor synchronization is necessary.
Always refer to the download factory service manual when performing work on an outboard. Additional idle adjustment procedures and critical specifications are listed, and often differs between year and model.