scootertrs

After 818 sits for a couple of days, when I try to start, I have to manually pump the fuel. Holding the pedal about 1/2 of the way down, she starts right up but shortly thereafter, she dies and after repriming and cranking the engine for a while she then starts and runs like a top.I noticed that when I manually pump the fuel, the pressure gauge shows 60+ psi pressure but when running, the gauge shows zip. I saw where the op manual states that priming be performed at low temperatures, but says nothing at normal temps. I have never gotten a reading from the fuel pressure gauge though she runs at highway speeds without difficulty. Is my primary fuel pump shot?
Thanks

pmramsey

The fuel pressure gage on the priming system reads "0" in normal operation. The priming switch must be off after priming. I have never used the priming system in either of my 818s even when in the mid-20s F. They both fire off the first time. Sounds as if you are loosing fuel presure after the initial start-up.

scootertrs

Right, but after she starts up the second time, she runs great. and if I shut her off and restart a couple of hours later, she goes just fine. It is as if I develop an air bubble in the system, and when it starts, it is ok until the air bubble gets to the ip.

pmramsey

I agree with you on the air. Have you tired starting it while drawing fuel from the other fuel tank?

73m819

Air

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Ron
Gainesville, Ga.
vietnam-1/66-8/68
42 5t? autocar tractor, gone
43m20, 12t, converted to tractor, gone
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DaveP

good chance its the selector valve.

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	3 way fuel valve 001 (Small).jpg (51.0 KB, 27 views)

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ca1517

If not the selector valve, I would suggest checking the rubber hoses that come and go to the selector. They are bad about cracking.

scootertrs

no, I haven't. But I may do a "hose changeover" since they are the original ones and almost 40 years old now. Good idea on the tank tho

Floridianson

Almost needs to be a sticky about what to do to these trucks asap. Fuel and oil filters. If you have slector fuel valve change the rubber hose if not new. Check primer hose for cracks or leaks Check gear oils. Check antifreeze PH. If intanke fuel pump check presures there is more but I just woke up and got sleepy head.

Also the smaller hose goes on well and bottoms out well. The larger hose needs to be set in the sun and a little rubber lube put inside the hose with a Qtip is how I get it all the way on when the slector is still in place.
All the ones I have seen so far a barb fitting so just slice off and replace without hose clamps.

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James
1 Bobbed 5 ton with lockers in rear and W/W
30 Outher Military Trucks
4 Military Cranes
3 Military semitrailers
2 Military expandable semitrailers
3 military gens. 3k 5k 10k
And storage of to many Military parts that it might be a sin.

kc5mzd

The primer pump injects fuel into the intake manifold. It doesn't prime or pressurize the IP. The reason you start then die is because the engine burns off the fuel in the intake manifold.
It sounds like a air leak somewhere in the fuel system. The hoses going to and from the fuel selector will leak air if they get even the smallest crack. Your best bet is to replace them if you just got the truck even if they don't look bad. This will prevent problems on down the road.
I used a clear nylon tube in mine so I can see if it is getting air. I don't know how long it is going to last but it works good for now...