Mercury 40 HP problem....HELP!!

[Cane Pole]

I think I may have posted about this once before, but it's back, and worse. I have a 2002 Mercury 2 stroke 40 HP with auto oil injection. When I run in low RPM, it dies or runs really sluggish. I had this issue before and was advised to idle it up, which I did, along with changing the plugs and it seemed to work, but now the problem has returned. Only now I have trouble getting it refired when it dies. I have to put the throttle at least half way(in neutral of course) to get it to start sometimes after it dies or after it sits off for a while when I shut it off to fish. Also, late in the day last time out the motor ran extremely sluggish even throttled all the way. Almost like the boat was really loaded down. I took the plugs out today and found the lower plug had quite a bit of oil on it. I cleaned it off and plan to change both along with the oil filter, but I can't figure out why they keep fouling every six months or so. Is it because I need to run a higher grade gas? Could the oil injection be adding too much oil? Not enough gas through carb? Is there a carb cleaner that I can run through it that works at all? Sorry for all the questions. I really don't have the funds or time right now to take it to the shop. If it's something short of tearing the carb apart I can probably do it. Please help.

By the way, I use regular grade gas and Pennzoil Marine XLF oil, if that matters.

I am no mechanic, but fuel fowled plugs tells me you may have ignition problems.

Also, I had 40 Mariner with similar prob. Cleaned carbs, replaced jets. Fixed it.