2018 Mercury 150 Pro XS with 23 hours - engine stumble/miss on moderate to heavy acceleration, starting seeing what I considered excess smoke as well...reminded me on my 80"s XP evenrude.
Have taken twice to dealer with no codes,no problem found..feels like a coil pack breaking down,definatly worse with additional load in the boat
Just seeing if anyone has had similar issues

Kinda surprised the ECU didn't pick it up. Might pull/inspect spark plugs to help narrow down which cylinder affected.

Yeah..the shop was surprised as well...se one time around had video in which you could plainly hear the cutting out..will ohm out coil packs and check plugs

My 2017 150 pro xs smokes a little but runs like a scalded dog. I was thinking the smoke was just cause I needed to top off the tank with some fresh fuel., or I may have added too much fuel treatment.

Could be fuel related such as one of the diaphragms in the fuel rails

we can check it out for you if need us to. Pm me if need to

I read about this being a problem a lot! First thing I�d have the mechanic check.

Pull the fuel filter out and look in the bottom of the reservoir, see if there is amber colored scale material in there. If so clean it out put new fuel filter in and new fuel line as well.

Replace them plugs!

Agree: Could be fuel related such as one of the diaphragms in the fuel rails

Had same problem with mine ended up being fuel diafram. Replaced no problems since

Will do..thanks,

Quick update...after a total of 3 weeks downtime in both locations of a local dealer( in Hurst and Cleburne) but no names ....I have been told they found all 4 plugs were fouled and needed replaced...when I pressed them a little I was told that during break in it is programmed to double oil for extra lube...ok I knew that..but unit is not in "break in mode" any longer...so basically I have a Mercury that only has 24 engine hours and is 8 months old that I am being billed for...sound crazy or is it me?
And by the way...no codes and fuel rails were said to be fine

Lots of idling and short trips at low rpm's will do that every time.