98 Big Bear 350 - exhaust glowing red

I just noticed yesterday after about 10 minutes of use that the exhaust pipe close to the engine was bright red. I've read that it may be running lean, if yes how would I adjust this. Also if someone can tell me the correct oil to use as I think it is time to replace it.

Has anyone seen this before?

I've seen this if the machine is standing still and running at high idle the pipe will get red hot, the oil should be 10/40 of whatever flavor you like.