Originally Posted by wmeabates
If You have some extra pulleys try a smaller one on the pump,or a bigger one on the crank.That will speed the pump up.Maybe both but don't exceed the rpm limit of the fan blade,very important. Sometimes less mechanical advance in the dist. and more advance at idle will help at low speed also.Bill.
Yep also check carb settings, i would also drop the flex fan, they are designed to reduce drag on the engine, imo with smaller blades, coupled with any flex that may happen at low idle. low speed cooling, is compromised.