2019 Mercury 150hp four stroke miss

[twinmercs]

Hello All. I am looking for some help. I have twin 150hp mercury four stroke out boards. I am having different problems with each but the one I need help with is, I fish alot in the ocean and always leave one of them running to keep batteries charged. My port motor seems to load up and start missing after a bit. Ill run the rpm's up moving to another spot. After a bit it smooth out, the after idle a bit does it again. I run non ethanol gas only, with fuel treatment. I changed the plus with no change. The starboard motor never does this so I don't believe it to be a fuel issue. Can anyone point me in the right direction. Thank you in advance.

 

[iang6766]

Identify misfiring cylinder and swop coil pack with another cylinder and see if the miss follows the coil. They are known to fail.

 

[twinmercs]

Identify misfiring cylinder and swop coil pack with another cylinder and see if the miss follows the coil. They are known to fail.

I will try that, thank you.

 

[twinmercs]

Identify misfiring cylinder and swop coil pack with another cylinder and see if the miss follows the coil. They are known to fail.

How would to figure out what one is misfiring? Pull plug wire one at a time? Thank you in advance for the help.