Is the fuel cell pickup replaceable???

[rmoore0852]

Puma Unleashed 356QLB. Has anyone ever dropped their fuel cell to replace the pickup? My generator won't run below a half a tank. Runs fine until the gauge reads just a hair over a half tank, then won't suck fuel. That is unacceptable for the boondocking that we do. I know that the problem is in the tank. Fuel line is good. Generator runs fine with the fuel line in gas can. I have a clear fuel filter installed inline and can see that it is running out of fuel. I'm thinking that the fuel pickup tube in the tank is rotted out from the previous owner leaving old gas in it. I'm guessing he left just over a half tank and it corroded the pickup at that level, causing an air leak. I'm planning on dropping the tank tomorrow, but here is my question. Is the fuel pickup assembly replaceable or am I going to have to replace the entire fuel cell? If so, any idea on cost?

[rmoore0852]

Update. Installed the new pickup today. Added 8 gallons to the 30 gallon tank. Gauge shows just a hair over empty. Ran the gen for over 2 hours with the AC on in the camper. No issues. At least for now I'm going to say that it's fixed. Anyone having these type of issues, consider dropping the tank and replacing the pickup. It's not that hard a job and seems to have fixed my problem. I will be giving it a good workout over 2 trips in June and will see if there are any issues.

[nayther]

rmoore0852 wrote:

nayther wrote:
I'd check that fuel line with some air for a leak. Take it loose at the tank and plug it, then put about 10 psi in it and see if it holds, check for leaks with soap bubbles. You may have a small leak somewhere else that's causing the pump to suck air. It is possible that the joint in the tank is the culprit but I'm not convinced; if it was that bad of a leak I'd think the fitting would fall off. Maybe JB weld it together?

I intend to do that also, but since it runs fine down to about a half a tank of fuel, my thinking is that is must be tank related. If it was a problem in the fuel line, wouldn't it act up no matter how much fuel was in the tank?

Maybe..........the height above the pump is part of the "net positive suction head" (NPSH) and it helps overcome the inlet line pressure loss, it's possible, up to 1/2 tank, that there's enough NPSH to negate the leak or a weak pump suction.

[rmoore0852]

nayther wrote:
I'd check that fuel line with some air for a leak. Take it loose at the tank and plug it, then put about 10 psi in it and see if it holds, check for leaks with soap bubbles. You may have a small leak somewhere else that's causing the pump to suck air. It is possible that the joint in the tank is the culprit but I'm not convinced; if it was that bad of a leak I'd think the fitting would fall off. Maybe JB weld it together?

I intend to do that also, but since it runs fine down to about a half a tank of fuel, my thinking is that is must be tank related. If it was a problem in the fuel line, wouldn't it act up no matter how much fuel was in the tank?

[Bedlam]

Here is a link to the marine filter above: http://www.attwoodmarine.com/store/product/in-line-fuel-filters

Any of your local boating stores or favorite online shops should have these or a competing brand. I use them in my off-road toys too...

[rmoore0852]

Rambino wrote:

Bedlam wrote:
Make sure the filters you guys are using are for gravity fed high volume applications. I have run into some fuel filters that were restrictive in low fuel pressure applications also causing starvation at higher loads. I have been using the filters for outboard motors with marine external tanks with good success.

Do you have more info on the filter you use? Make, part #. A search came up with a variety of filters. The photo shows a filter with threaded fittings. Would have to add Threaded fittings to fuel hose. Increasing the possibility of leaks, air suction. I wonder if filter location could be a issue as well.

I have used these filters before, in other applications. They do have threaded ends, but they come with the different size hose barbs. I have never had leakage issues with them, but I always use Teflon tape or a little pipe dope to seal threaded connections. You can get them at auto parts stores in the hot rod section, or a marine stores (more expensive there). If I still have issues with the current filter I'm using I will get one of these to test with. I'm still probably going to install an inline pump back near the tank. Sounds like these Onan pumps are just barely powerful enough to pull fuel all the way from the back.

[Rambino]

Bedlam wrote:
Make sure the filters you guys are using are for gravity fed high volume applications. I have run into some fuel filters that were restrictive in low fuel pressure applications also causing starvation at higher loads. I have been using the filters for outboard motors with marine external tanks with good success.

Do you have more info on the filter you use? Make, part #. A search came up with a variety of filters. The photo shows a filter with threaded fittings. Would have to add Threaded fittings to fuel hose. Increasing the possibility of leaks, air suction. I wonder if filter location could be a issue as well.

[nayther]

I'd check that fuel line with some air for a leak. Take it loose at the tank and plug it, then put about 10 psi in it and see if it holds, check for leaks with soap bubbles. You may have a small leak somewhere else that's causing the pump to suck air. It is possible that the joint in the tank is the culprit but I'm not convinced; if it was that bad of a leak I'd think the fitting would fall off. Maybe JB weld it together?

[Bedlam]

Make sure the filters you guys are using are for gravity fed high volume applications. I have run into some fuel filters that were restrictive in low fuel pressure applications also causing starvation at higher loads. I have been using the filters for outboard motors with marine external tanks with good success.

[rmoore0852]

Rambino wrote:
I added an inline clear fuel filter and started having running problems. It ran well when the tank was full but the fuel pump was making noise. It ran poorly (lean) when the tank was near empty. I removed the filter and all is good! The filter never filled with fuel. You could see the fuel flow through the filter but not fill it. I put the filter in to prevent stuff from when the RV was built getting to the gennie. Plus extend the life of the onan oe filter which is kind of hard to get to and rather expensive.

Wow, interesting. Mine will run fine through the filter with the line in a can of gas, but sounds very similar to my issues. It looked like the filter always had air in it, but would fill enough to work. The fuel coming out of the line would kind of sputter and splash into the filter. As the generator ran with a load, it would use fuel faster than it was coming in. I thought that it was sucking an air/fuel mix from the tank. I initially added the inline filter because my generator compartment is rather small and I absolutely can not change the Onan filter without removing the exhaust, unbolting the entire generator, and moving it sideways enough to get clearance. Not exactly something I can do at midnight in the middle of nowhere when the Onan filter decides to clog up. Since it's free, I will install the new pickup tube and put it back together. If it still acts up, I will remove the clear filter and try it again. If that is what mine is doing too, I am going to look at adding an inline electric pump. With the way my generator is enclosed, I cannot take the chance of the Onan filter clogging while we are camping.

[Rambino]

I added an inline clear fuel filter and started having running problems. It ran well when the tank was full but the fuel pump was making noise. It ran poorly (lean) when the tank was near empty. I removed the filter and all is good! The filter never filled with fuel. You could see the fuel flow through the filter but not fill it. I put the filter in to prevent stuff from when the RV was built getting to the gennie. Plus extend the life of the onan oe filter which is kind of hard to get to and rather expensive.

[rmoore0852]

Plastic tube looks fine. No signs of pinholes or any damage at all. Called ECI fuel systems, they are the manufacturer of the tank. Great customer service, they are sending me a whole new pickup assembly at no charge. They even did 2 day shipping, since this weekend is my last chance to work on the camper before a big trip in 2 weeks. Hopefully this fixes the issue. I'll keep you guys posted.

[Bedlam]

rmoore0852 wrote:

Bedlam wrote:
Could your fuel pump be going out and it is too weak to lift fuel once the tank runs down?

I have definitely considered that, but when running from the gas container, it was a quart container on the ground. A good 18-20 inches lower than my fuel cell. I would think that this additional lifting distance would have caused more problems. I don't know how to strain the pump any more than that. It ran perfectly for an hour before hooking back up to the tank, where it died within 5 minutes.

It sounds like the pump is fine. I would lean toward a leaking pickup fitting or line like others have posted.

[Retired_JSO]

Could the plastic line have a pin hole in it around the tank level it stops running?

[rmoore0852]

Bedlam wrote:
Could your fuel pump be going out and it is too weak to lift fuel once the tank runs down?

I have definitely considered that, but when running from the gas container, it was a quart container on the ground. A good 18-20 inches lower than my fuel cell. I would think that this additional lifting distance would have caused more problems. I don't know how to strain the pump any more than that. It ran perfectly for an hour before hooking back up to the tank, where it died within 5 minutes.