04 TGB with Morini engine runs bad when warm

[fixitdave]

I found the ground wire off of the coil. Cleaned everything n put it back rite. Still same... Runs fine the 1st 10 min, then it acts almost like the fuel line is being intermittently pinched. Won't idle, give it a lil throttle n it sputters, a lil more, more sputter, then it takes off. I've taken the carb apart n cleaned it a cupple times, new plug, different intake tube. No oil injection, so Can I be adding too much oil at 4 oz per gallon? Could it be low compression? It has a bit over 15k miles on it, but someone changed the jug n head at some point cuz there not stock Morini. They are DR racing. Any Ideas??? Please and Thanks Guys.