slow acceleration

[Twannie]

hello there,
When I have taken my '67 912 for a long trip and the engine is hot, it sometimes takes ages to accelerate from 3000 to 4000 rpm (or higher). Especially in 3rd or 4th gear. It never happens when I drive the car for a few miles. To make it more complicated, it doesn't always happen. Does anybody know a possible cause for this problem?
Thanks,
Antoine, The Netherlands

[dimps8]

Hi Antoine,

Maybe you could start by checking the mechanical advance when your cars hot like you said. The advance maybe working at lower temps and sticking when hot making the engine a stone. Also suggest the acc. pumps on the carbs are spraying correctly.

Damon