You should expect very low vacuum - 0 to 2 inches with a clean filter element. 13 inches of vacuum at idle is way high. One assumes this gauge is in the fuel line after the Racor and before the lift pump and that the gauge reads 0 when the motor is off. If that is so you have a major restriction somewhere between the gauge and the tank. This includes the filter element, a pathway in the filter head, the fuel shut off valve, the dip tube (some have a screen at the dip tube tip - if so remove and discard) and any (collapsed or fouled) lines that connect these items.
I would be surprised if the motor could manage any power at all. Excessive vacuum will damage the lift pump diaphragm so find the restriction now.
As to the R12 model there are three values - R T S. The T (10 mic) is the better choice. The S (2 mic) will foul about 5X sooner than the T and flow 1/5 the volume of the T.
Charles
