Yesterday I replaced the valve cover gasket on my b230a 740. It stil leaks oil from under the valve cover near the back of the engine. Is this normal for a new gasket, or did I do something wrong.

I used some force, but not much, when I tightened the nuts. A friend told me to use little force, but I have a heavy hand. Is it correct that to much force will crack the gasket and make it useless.

I need to do this quickly, before the winter really sets in.

I'm almost 100% sure that this is not excess crankcase pressure, since I have cleaned the flametrap and surrounding hoses.

Thanks for any help :)