Originally Posted by tex1

If you are having problems with temp change from day to night then your plug is very boarder line. If you bump the temp up on the plug it will, in most cases and for most engines, solve this problem.
This is why most every OS engine you see out there runs the OS p3 or p4 plugs all the time.
Find you a GRP #4 plug and get back with us.
All of our customers love these engines when they get the right plug in.
TEX