I have an old home made go-devil that I have used for many years with a 8hp and a 12hp motor. This year I put a 16 hp on it and the u-joint runs over 200 degrees. I think the u-joint is in good condition and I tried more grease/less grease. The design is when we ran the angle at 15 degrees because the old small hp motors were slinger lubricated and if you put too much angle the front bearing would starve for oil. I am thinking about taking some of the angle out, any other ideas would be appreciated.

sounds like our on the right track to me.

Pull the u-joint & check both surfaces for movement. Signs of wear on either may be an indication that you have bad bearings in at least one of the yokes. Even if no signs of wear are evident, changing the u-joint is a pretty cheap start in the right direction. Bad bearing = friction = heat .. Much luck to ya!