If you didn't mess with the pump, ie taking the AFC housing off, 3 things that are very common on the P7100 pumps in both the B and C series. The first and easiest thing to check is the FSOV link and capscrews that hold it to the AFC and governer housing. The bolts come loose and/or fall out and won't let the FSOV pull the lever that pulls the rack to full fuel, symptom, low power and sometimes hard to start, depending on how loose the bolts are. Check the link on the FSOV..fuel shut off valve...if it's the older small type, apx 1.5" dia and 2.5" tall, the link breaks in the middle, again, symptoms are low power and sometimes hard/no start. 2nd, the overflow valve at the fuel pump outlet, or return. This valve is a spring loaded check valve. It holds the low pressure that the lift pump makes in the gallery of the P7100. If you don't make the correct ammount of low pressure fuel, the high pressure won't be right. Symptoms, low power, slow acceleration, sometimes white smoke at higher RPM, hard starting. The gallery pressure should be apx 25 PSI at idle, 32+, high idle, no load for a good valve. If you have no way to check pressure, just change it. It's very easy to change. 3rd, the AFC line from the intake manifold connection to the top/rear of the fuel pump. The fittings work loose, wallow the steel fitting and bung in the housing and make it so the AFC can't respond to the manifold pressure, ...it vents manifold pressure to atmosphere instead of letting the pressure push on the AFC diaphragm. Symptoms, just plain low/no power and slow acceleration. I can probably scan some manuals to show you what to look at. PM me if you need pics. Good luck, try to keep us posted. Stay safe and THANK YOU!
