Case 504 fuel system question

Hydropower · Aug 12, 2019

I have a Case W20C loader with the case 504 engine. (1984) After about a week the fuel drains and it starts hard. If I let the electric fuel pump run for about 2-3 minutes it fires right up. I put a check valve on the low pressure side thinking an air leak caused fuel to drain back to the tank. Wasn t it. So now thinking it s the fuel return check valve on the injection pump? Hopefully someone with some experience working on the case 504 s could lead me in the right direction. Any advice given is much appreciated! Thanks!

Nedd · Aug 12, 2019

Sounds like an air leak. Fuel filter gaskets? Primer
pump on the side of the injection pump? Or even
not venting the fuel tank? Vacuum sucking fuel back
to the tank. Lots of possibilities

r.w.b. · Aug 12, 2019

I had a 1370 that would do that if tank was half
full.id pump it up n it start just fine

Eagle Doc · Aug 12, 2019

The return fuel check valve can cause the problem. I don't know anything about your loader but if the fuel level in the tank is lower than the pump that can happen. Since you have and electric pump on it I would just run it as you have been and not worry about it.

DKase · Aug 12, 2019

W14 does the same thing. There is a check valve in the suction line just above the fuel tank. It gets small pieces of junk in it
like flies wings and that allows the fuel to slowly drain back to the fuel tank. I have the manual primer pump on mine, and if it
sits more than a day I give it a few pumps and it fires right up. I have tried cleaning the check valve and it lasts a week if I
am lucky. I have a couple neighbors that have W14's also and have the same problem. We all have decided it is not worth the
trouble to clean the check for the little good it does. I have thought about an electric pump, but if it takes 2 minutes to pump
up I am better off with the primer pump. I suspect yours is draining back to the tank and your electric pump is trying to pump air
for the first 2 minutes before it gets fuel to pump. You might want to try to mount your electric pump below the fuel tank so
there is fuel to the pump at all times. It should not take the electric pump more than a few seconds to pump fuel to the injector
pump. Good luck, let us know if you come up with a good solution.

Hydropower · Aug 13, 2019

Thanks for the reply's! Good to know this is somewhat common. I did install a check valve between the manual priming pump and electric fuel pump. The electric is mounted on top of tank so definitely could take time to prime perhaps sucking air. I will definitely post a fix if I figure it out. Im going to clean the check valve on injection pump return. I ll give it one good cleaning then deal with it if problem persists as you described. Just knowing this is common certainty makes me feel better. Thing fires right up two days after running, anymore than that this happens. The longer it sits the harder it starts. I think i ll give that manual primer a few pumps to help the electric get a prime. Maybe that will do the trick. Certainly can t hurt! Thanks Again!

DKase · Aug 13, 2019

FYI the top of the fuel tank is the level of the bottom of the oil pan. Fuel tank is under the radiator.

Case 504 fuel system question

Hydropower

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Nedd

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r.w.b.

Well-known Member

Eagle Doc

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DKase

Well-known Member

Hydropower

New User

DKase

Well-known Member

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