Fuel tank pump problem

[Palmetto Bug]

I have an auxiliary diesel fuel tank for filling the tractor. Suddenly it won't pump.

It has a Fill-rite Tuthill electric pump. The vanes and rotor look fine. The check valve looks fine.

When I run it, no fuel comes out and when I take the filler cap off, the tank is pressurized.


Anybody ever run into anything similar and have a suggestion?

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[MolliesMaster]

How does the fuel look down in the tank?

[goob]

Polarity on your battery connection

[Palmetto Bug]

That occured to me. I checked the polarity, not only with a meter but I also checked the shaft rotation. The pump is turning in the correct direction.

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[Palmetto Bug]

Tank is full with fresh fuel.

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[thunderchicken]

It doesn’t take much wear on the vanes for them to stop pumping. On some models you can take the vanes out and turn them around. See if that works. If not, I would order new vanes. Sadly, the newer pumps don’t last very long. If you have to replace it, I would go with a GPI.

[Palmetto Bug]

Not sure the vanes can be turned around. They have a groove in the leading side to pass the fuel that provides the pressure to expand them.

I have found rebuild kits for around $90 that have a new rotor, new vanes, new face plate, new check valve parts and all seals. The parts in it don't look particularly worn. This thing worked fine a couple weeks ago. If it was wearing out, it seems like it would have gradually gotten bad but this thing just suddenly quit, coincidentally with this cold snap.

What is typically on the suction tube down into the tank? This is one of those 100 gallon L shaped tanks made to fit in front of a truck tool box. Is there any screen or check valve built into it that might need inspection?

Is there some process to prime them when they are first installed? I tried pouring fuel into the suction side at the filter and even tried pressurizing the tank with air to get it primed.

[Whackumstackum]

Thinking east first did the Fuel gel in this cold weather? Water in the separator frozen? If not rebuild pump and roll on.

[cam1195]

Vane pumps are positive displacement, which means self priming.

You say the tank is pressurized when you removed the cap? Is the tank vented? I suppose you have used the pump before on this tank but I’m not sure how a positive displacement pump can work with a tank that has no vent. What goes out must replaced with air. My guess from a theoretical standpoint is that the pump can’t work without the tank being properly vented. Try pumping it without the fill cap on. If that doesn’t work, try pumping without the fuel filling nozzle on. Could be the nozzle.

Another issue might be that the suction pipe has an air leak in it somewhere. Imagine trying to use a plastic straw with a crack in it. The pump won’t be able to self prime. If it’s one of the telescopic suction pipes, check the joint connecting the two pipes. Check to make sure your suction pipe isn’t too long. There should also be a screen on the suction side of the pump. I wouldn’t think that’s your issue if you just recently used the pump, but maybe you’ve got some crud in your tank.

[Palmetto Bug]

I've tried it with cap off, filter removed. The fuel is relatively fresh. Tank was emptied a few weeks ago and refilled with fresh fuel. If the suction tube is perforated, it would have to be at the very top.

Maybe the shaft seal is leaking and letting it suck air. Rebuild kit has been ordered.

Thanks for the replies. I'll report back when I get it figured out.

[thunderchicken]

Its probably either the vanes or the seal on the check valve. I have around 200 of them on customers tanks and 99% of the time that is the problem.

[Palmetto Bug]

That's what I was waiting for....someone who has dealt with these pumps failing. When I get the kit, I'll try replacing the check valve, rotor and vanes before I go to the trouble of swapping out the shaft seal. Thanks for the reply.

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[Palmetto Bug]

Now I'm totally stumped. I got it working but it wasn't due to the $90 rebuild kit. After replacing the rotor, vanes and check valve parts, it still wouldn't pump and I could feel it draw a vacuum on my thumb at the nozzle. I rechecked the polarity at the hard wired connector on the tractor and it was correct but just to see what would happen, I reversed the hard wired two conductor pigtail plug coming from the pump and it pumped great. I have no explanation. Everything has been working for years and nothing about the wiring has been changed. Suddenly it needed the wiring reversed. I may take the switch housing apart to see if there is any way the pump switch could have done something to cause it. Either way, it is now working but it's going to bug me until I figure out how it changed.

[reeltight]

My drill has done the same thing recently. Forward is reverse and reverse is forward. I assume that it probably has something to do with the magnets.

[HARV]

They've become bipolar.

[Palmetto Bug]

They've become bipolar.

I just hope it's not contagious and the earth's poles swap places.