I have a 04 Mercury Opti 150 (250-300hrs) which was running fine until a recent fuel filter change. Now it dies until warmed up at idle, hole shot slowed and will not run above 4500 rpm. The fuel filter appeared to be slightly bent at the water sensor but no other obvious damage. Is there a bleeding process that I don’t know about? Possible causes? No alarms going off with the Smart Craft. Thanks in advance for any suggestions.

Check fuel lines, primer or fuel pump. Lines can collapse, or suck air, primers bulbs can go bad, fuel pump may not be working 100%.

I changed the fuel lines and cleaned the VST which through research I would have thought might have been the cause. It was not so I decided to look at spark plugs and they were fouled. Changed them and now runs good again. Thanks for the reply Alumacraft 14.