Hey guys how often do you take your boat in for a tuneup or how often do you change the sparkplugs. I have a 150 Mercury and I do not know if it needs plugs or an adjustment. When idling it may cut off or if another boat is near you can not hear it. What do you think?

What year and model Merc?

It's a 1994 Mercury

I get new plugs every year at the end of the season then check over the motor while I'm winterizing it.

Change the plugs and check/change the lower unit oil annually in the spring.  Also check the compression.  I wouldn't change my plugs in the fall and then winterize it and add all the fogging oil to new plugs.

I also change the element in the water/fuel separator at least on an annual basis.  Rotten ethanol.

Since my Yammie is 4 years old the entire water pump gets changed/rebuilt this year too.

Like they say....."an ounce of prevention beats a pound of cure every time".

Shortbasser