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Shari WellsJul 30, 2025
What to do if my MerCruiser Engine fluctuates slowly at idle?
- LLuis ClarkJul 30, 2025
If your MerCruiser Engine is running rough and the vacuum reading fluctuates 4 or 5 inches very slowly at idle RPM, it could be due to several reasons. The carburetor might need adjustment, the spark plug gap might be too narrow, or the valves could be sticking. Adjusting the carburetor and checking the spark plug gap may resolve this issue.