NEED HELP!! 25 hp Mercury

[spark plug]

I have a 89 model that runs great on lower cyl. top cyl not running. I have checked both plugs, and they are both firing while removed. I pulled exhaust cover and piston and cyl. looks ok. good compression also. Can you help??

 

[rodbolt]

Re: NEED HELP!! 25 hp Mercury

have you tested the coil primary voltage while its running? you can also swap coils to see if the problem moves. also remove the carb and carefully inspect the reeds. they were noted for chipping the tips off.