Because it seems to be worst, the longer it sets, then we would first suspect that somehow "air" is being allowed to get into the fuel system.

Note: 3208 fuel system is almost 100% suction, it only get pressurized, once it gets inside the fuel injection pump/governor housing area.

Now, some causes that allow air into the system are:

1: failed anti-siphon valve(part of bleed valve, that has the tee handle on it on top of the pump)

2: leaky throttle shaft governor seal(previously mentioned)

3: loose fitting or gasket ANYWHERE in the entire fuel supply system

4: leaky hand pump(previously mentioned) Remember, this is all part of the suction side, so you won't see fuel leaking out

5:cracked fuel tank stand pipe(inside tank)

6: something has been rubbing the fuel filter and worn a pin-hole into its metal can, that allows air to enter.

7: lack of sealing at the fuel/water separator glass bowl mounting

8: loose bleed valves(either on top of pump or at fuel/water separator)

9:leaking lip seal in the shutoff housing area(under electric shutoff solenoid)

10:Worn lip-seals at transfer pump area, on front of fuel injection pump(behind drive gear)[You can't see them.]



Probably should just go ahead and put on new fuel filters, pump up the fuel system, and see if it starts.(bleed steel injection lines, if it doesn't fire up) If you have two people, then one guy can hand pump(while cranking), and the other guy can turn the key. As the other guys said, if you see fuel coming out the hand pump, while pumping, then you should go ahead and change it. [new hand pump and new gasket]

Reason for new fuel filters, is because these engines are really sensitive to fuel RESTRICTION on anything in the supply of fuel TO that injection pump. The harder that little transfer pump has to work, then things like the rear governor throttle shaft lip-seal want to start "sucking air", too.



What is really needed is a "sight glass", in-line, on the fuel supply line that goes into the top of the fuel injection pump. That would help us t/s and verify these website guesses.

Now, there is always that possibility, that the problem that Dr. Z described could just be getting worse(rusty linkage, or binding in internal linkage, inside pump itself) and we are incorrect about air entering the fuel system. If you could be more descriptive about the first time it just started to crank longer, it would help analyze this.(did it misfire with some white smoke out the exhaust OR did it act the the RPMs just very slowly increased, but the engine actually sounded smooth, when it did start-up slowly????????)