excessive white smoke

  hello I have a FL40  Allis fork lift with a Buda G-153 engine and it has a  carb it started smoking real bad it would fill a 2500 sq ft building in seconds so you could'nt see 20 ft away the engine runs ok no engine miss dead cylinder  It had a coolant smell to me so I pulled the head expecting to see a blown head gasket it wasnt blown sent the head to machine shop had it pressure checked it is ok.  What can be the problem? Only other thing to note is it is a bit overfull on oil not with antifreeze but gas smell  this thing is not used very often and short running times that is what I contribute the over fill and smell in oil

thank you we were thinking that also since there was no head problem the smoke i thought had a antifreeze smell maybe just in my head.  thanks again