The engine must be at NORMAL OPERATING TEMPERATURE for this adjustment. Two
items of test equipment are required: an inductive pickup timing light and either a Scan Tool,
Diagnostic Code Tool, or MerCruiser Special Timing Tool (91-805747A1).
1. Connect timing light to number 1 ignition wire.
2. Connect the appropriate tool to the DLC connector of the wiring harness.
NOTE: The 7.4L MPI will automatically adjust engine to approximately 1200 - 1500 rpm
when put in the service or timing mode.
3. Manually adjust the engine throttle to 1800 rpm + 200.
4. If Not Using MerCruiser Timing Tool: With engine running, set the scan tool or Diagnostic
Code Tool to service mode.
5. Shine the timing light at the timing mark indicator located on the timing chain cover.
NOTE: If adjustment is needed, loosen the distributor hold-down bolt and rotate the
distributor clockwise or counterclockwise to adjust the timing. Then repeat the timing light
check until the specification (8 degrees BTDC) is met.
6. Torque distributor hold-down bolt to 30 lb-ft (40 Nm).
7. Set Scan Tool or Diagnostic Code Tool to normal mode. If using the MerCruiser Special
Timing Tool, disconnect it from DLC connector.
8. Manually close throttle to bring engine down to idle state.
you can do this with a paper clip, short a and b together