Turning engine off noise

[sainoz]

Hi hoping for some assistance. I have a 2011 Bayliner 175 3.0 TKS Mercruiser and when I turn the engine off it makes like a coughing noise, engine shaking while it turns off. takes about 30 seconds and then no issue. Just wondering why the performance after switching off? Should it not turn off with no noise?

 

[dubs283]

dieseling, not healthy for any gasoline engine

likely causes are running rich, improper timing, idle speed too high, carb settings/needing rebuild, etc...

best to start with a full tune up including fuel filter(s)

 

[nola mike]

Hi hoping for some assistance. I have a 2011 Bayliner 175 3.0 TKS Mercruiser and when I turn the engine off it makes like a coughing noise, engine shaking while it turns off. takes about 30 seconds and then no issue. Just wondering why the performance after switching off? Should it not turn off with no noise?

Yes, you're dieseling. Uncontrolled detonation after you shut down, yes it's bad. Timing, carb problem, running hot, carbon in the engine, other causes. Is this all the time or only when running hard? First step would be to let it idle for a minute before shutting down. If it does start to diesel when you shut down, turn the ignition key to "run" so the engine will start again. Then wait a bit before turning back off