Mercury ingition

[gapster]

I belive I am having ignition problems with my 90 HP Mercury. It feels normal at 3000 but intermittently jumps to 3500, no miss, no sputter, just in and out. It could be a cylinder cutting in and out but feels more like ignition advance/retard. I'm on my way to get new plugs. Any other suggestions?

 

[Chris1956]

Re: Mercury ingition

Inspect the old plugs for color. Suspect any cylinder that has a plug that looks different. Do compressiopn test and spark test. Report back on results.