2009 Merc 25 HP 4-stroke

 

What the heck is that?

It's mentioned in this service bulletin/ recall they put out but I don't have the time to read the entire reason this morning.   http://www.marinepartsexpress.com/Merc_Product_Bulletins/Official Recall Notification U.S. Federal Boat Safety Act - Throttle Bulletin No. 2006-14.pdf

I believe that disengages the "shifter" from the throttle.  So if you wanted to control engine speed without putting the outboard in gear, you can.

 

I imagine it is for older equipment that may or may not need some throttle manipulation to warm up to the point where it will idle.

 

My 80s Merc has that on the controls at the cockpit, maybe it is the same sort of thing, but back at the outboard?

A button?

nitrous.......? LOL

 

13 minutes ago, crypt said:

nitrous.......? LOL