Engine whistles immediately after it is turned off

[Teresa]

2008 350mag mercruiser, used all summer with no problems. All maintenance and service completed routinely by dealer. Yesterday it started making a whistling noise immediately after the engine is turned off. It sounds like it is sucking a big gulp of air in near the flame arrestor. Starts and runs fine.

 

[fastjeff]

Sounds like a vacuum leak to me. If so, the noise made with the motor running hides it until you switch off.

Look for a hose off or cracked open. Some folks spray starting fluid around the manifold, listening for a change in idle speed (which indicates where the leak is).

Jeff

 

[Docksidemarineservices]

If this is a DTS (Digital Throttle and Shift) Engine, This is normal.