You can just mark the F with a Sharpie but do it on the side which would face the hole , that way you can see it clearly , but its the second notch (if going clockwise) , is the Tensioner in a set when your noticing this ?? , it should align with a new chain , so not sure why it would be off , you can do a "test , by moving the chain 1 tooth and seeing if it makes a difference , but i would suspect it will be much farther off than it is now , did you try rotating the engine 1 or 2 revolutions by hand using the kick starter and your hand (with the spark plug out for ease of turning) and see if its still out ?? , hopefully after rotating the engine a few times , it will show it correctly .... report back with findings ....