Fuel issue
 

Ok heres a new one to me, the primer ball will not stay hard at low speeds for more than 2-3 min. and engine stalls. But everything at mid/high speed is fine. I checked all the fittings thinking theres a leak somewhere and can't find. Primer ball failing? Any thoughts would be great, thanks.

Have you recently installed any additional inline fuel filters?

It sounds like at low speed the engine is not producing enough vacuum to "suck" the fuel from the tank to your motor?

Could be an air leak on the line somewhere causeing it to leak down and not hold a good vacume and at high rpm the motor creates enough suction to pull the fuel to compensate for the loss. I would check around the connection points to make sure all are tight and clamped down well.