Lot of oil/gas under cowl

[kf4pfw]

150TL78S Johnson Seaking, 1978 model.

Noticed when I took the cowl off to check plugs etc that there is a lot of accumulated oil/gas around the base of the block. #1, what's the correct procedure for cleaning it and #2, is it something to be overly concerned with? I also noticed the other night that I am getting hesitation when I throttle up which I haven't had before. Set of plugs are on order and I'm thinking it may be time for a decarb? I decarbed it back this spring and it ran great for quite a while, now it's back to how it was: hard starting, rough/non-existent idle, hesitation and a drop in top end.

What do the gurus advise? Unfortunately, replacement is not an option at this point!

[kf4pfw]

ttt

[Lockjaw]

On an engine that old. I would be surprised if you didn't have sludge under the cowl. I would use an engine degreaser, and make sure none of it gone in the carbs, and rinse it carefully.