welcome.
first up, one thread is enough, someone will come along soon enough to help.
now to your issue. there are 4 screws down inside the cooling head on the engine. those need to be tight. but they also need to be tightened down a certain way. so lets start with taking those off, and checking the mating surfaces between the cooling head and the crank case. get some pics and post them here so we can see what it looks like.
be careful as there may be some very thin metal shims in place between the head and crank case.
then when you put it back together, run the 4 screws just finger tight, then turn them in a X pattern a 1/2 a little at a time until they are all tight. you want to tighten them down evenly.