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General Boards => Technical Support => Topic started by: Adam Hicklin on July 02, 2015, 04:58:57 AM

Title: Fuel filler tube problem
Post by: Adam Hicklin on July 02, 2015, 04:58:57 AM
On this most recent trip I have been having a problem getting fuel down the filler neck in to the tank. It almost immediately fills the tube and gurgles out the top, even putting the slightest amount in.  At first I thought maybe it was a volume problem at the truck pumps, but today I used a standard pump and it took me 30 minutes to get 25 gallons in.  It has never been able to take the full volume truck pump but I could always use the truck pumps at about 50% with no problem. Anyone have any idea what might be happening?  I've only tried with the tank 1/2 full or above, never below 1/2.  Same result the last 3 stops. 
Title: Re: Fuel filler tube problem
Post by: Roy 'Chuck' Tyler on July 02, 2015, 06:15:28 AM
I have to hold the nozzle on as it will kick off if I put it on the first notch of the handle.  I do use Pacific Pride and CFN exclusively because of convenience so I am always using truck pumps but a half tank will take about 20 or 30 minutes on either side on mine.  Maybe it is because of the cost of diesel going down because the dollar amount changing was limiting the speed of the pump when the price was so
Title: Re: Fuel filler tube problem
Post by: Adam Hicklin on July 02, 2015, 06:24:03 AM

Up until a week ago I could get a truck pump on the first click and leave it.  It would move along pretty fast.  Now I'm holding it just as it comes on and I have to watch and listen for the tube to fill up, hopefully release the handle before it comes spewing out the opening, at witch I'm about 50% successful.  Tremendously frustrating.  Heaven forbid I need to fill the tank.  It would take the better part of the day.  Most frustrating is I have no idea what changed.  One fill up it was fine, next it went wacky.

Thanks for your insight. 
Title: Re: Fuel filler tube problem
Post by: Roy 'Chuck' Tyler on July 02, 2015, 06:27:33 AM
Sounds like maybe the vent tube is plugged.  I don't recommend it, because it could be a real mess but until you get it fixed, you might loosen the cap on the other side to vent the tank.
Title: Re: Fuel filler tube problem
Post by: Joel Ashley on July 02, 2015, 07:39:08 AM
Not sure opening the opposing cap will work.  Others here know better than I, but I think at least some rigs have fill tubes in the form of a "Y", so tank air can't escape when the common pipe is taking fuel.  Regardless, the issue does seem symptomatic of a plugged, bent, or pinched vent tube.  Age, heat, and oil may even have caused it to collapse at a weak point;  our old Pace Arrow had that problem.

Title: Re: Fuel filler tube problem
Post by: David T. Richelderfer on July 02, 2015, 01:59:00 PM
I have found that if I can get the nozzle pointed towards the rear of the coach, then the fuel seems to "slide" down the tube at a faster rate.  Two near right-angle turns in the filling tube don't allow for a fast flow in the first place.  But if you can point the curved nozzle as much as possible towards the rear of the coach, then you are tending to bypass much of the first right angle.  The problems have been 1> having to hold the nozzle in that rear pointing attitude for the entire fill, and 2> many times the fill nozzle cannot be opened enough to engage the lowest flow setting on the nozzle's auto-fill catch.  I have tried opening the fuel fill cap on the other side, but I worry that will make a mess out of my sight.  I have also tried tipping the coach over a bit away from the fill side.  That seems to help the flow rate a little too.  But combining the "tipping the coach" with opening the fuel cap on the far side makes me even more nervous about making a mess, especially when the tank is getting full.
Title: Re: Fuel filler tube problem
Post by: Adam Hicklin on July 02, 2015, 02:46:06 PM
I've tried the nozzle in every conceivable position, same result. I only have 1 filler point on the passenger side, so no option to open the other port. Any idea where the vent tube runs on a Marquis?
Title: Re: Fuel filler tube problem
Post by: Dave Atherton on July 02, 2015, 02:47:48 PM
Gentleman I can relate to the above problem and with out turning the motorhome on it side to fill tank it was a 45 minute or longer tying up the fuel bay. Going deeper in problem,Monaco fuel opening
to tank was welded along side about inch down from top of tank. The fuel hose has a dip in hose
before fuel can enter tank. Another motorhome beaver 2005 same setup with wye connection about
12 inches before fuel line connects to tank along with a 2 inch dip in hose before entering tank.
looking at this 05 Beaver the vent for his tank is very small. It is a big project to drop down fuel tank
(using this 05 beaver) because it is over the steer axle and no room to get at connections so you
can slide off steer axle to ground. Reason we had the fuel tank dropped down was air leak in fuel
line top of tank. we could see the tank vent but could not reach it and we're getting over our heads
so we just addressed the air leak. Dave Atherton retired Cat Mechanic
Title: Re: Fuel filler tube problem
Post by: LaMonte Monnell on July 02, 2015, 02:48:41 PM
My Contessa is the same way. Spend a while filling the tank. The semi's come in and leave and I'm still standing there slowly filling up. Guess it's the way it is and have to suck it up so to speak!
Title: Re: Fuel filler tube problem
Post by: Gerald Farris on July 02, 2015, 03:24:23 PM
Since you did not say if you have a Gillig or a Magnum chassis, I will assume that it is a Magnum, and if so you must have a properly functioning vent check valve for the tank to take fuel at a fairly slow though reasonable rate. Removing the cap on the other side will not vent the tank since the filler necks enter the tank at about the 1/3 full level. Remove and clean or replace the vent check vale if the vent hose is good. If that does not repair your issue, and the coach fills much better from on side that it does the other, the rubber part of the filler neck needs to be replaced because the inner liner has probably come loose causing a restriction.

Title: Re: Fuel filler tube problem
Post by: Bobby Kirk on July 02, 2015, 09:35:23 PM
I have had several safaris and beaver coaches and feel for you. Thank the lord my 06 Marquis has a 2in pipe that goes straight into the tank in about 6-8 inches. I can run the big nozles wide open..nice.

Title: Re: Fuel filler tube problem
Post by: Joel Weiss on July 03, 2015, 12:50:08 AM
My Magnum chassis Patriot Thunder won't let me put the pump on the lowest detent but I sure can pump at ~10 gals/minute.  So a typical 60 gallon fill-up takes me ~6 minutes.  Not as fast as the 25 gals/min the truck pumps are capable of, but not excessively long, either.  I've timed it multiple times and that pumping rate is very consistent with the right side being slightly faster than the left.
Title: Re: Fuel filler tube problem
Post by: Adam Hicklin on July 03, 2015, 06:25:15 AM
Thanks guys.  Seems I'm not the only one with at least some variation of this problem.

Gerald, it's a Magnum chassis but I only have one filler port on the passenger side, just aft of the front whee, above the belt linel.  I got under there today.  There is what looks like 1.5-2inch curved metal pipe about 8 inches long. This is the filler body and cap.  It's connected to possibly a 2 inch rubber hose that goes down to the tank connection on the side, top of the tank, about in the middle.  There is a small 1 inch hose, which I'm guessing is the vent, that runs up to the filler body, next to the filler pipe and connects to something that I can't see.  The other end runs down, through the frame rail, to the tank connection which I can't see.  Where would the check valve be?  The filler tube has a slight dip, but it doesn't seem so severe as to cause this problem.
Title: Re: Fuel filler tube problem
Post by: Fred Brooks on July 03, 2015, 03:00:05 PM
        Hi Adam
   Not real sure on your configuration but a lot of manufacturers ran the vent hose back up to the filler neck just below where the recessed housing mounts. Remove the cap and look for an opening inside the neck with a flash light. Over time this vent hose may sag and create a "P-Trap" effect between the tank and the filler neck. If while filling at some occasion that occured, It creates a check valve effect and will not vent anymore. The best fix is to replace the vent hose but if that is not easy at least inspect and remove any low spots by re-routing if you can. I have had luck putting an air nozzle with a tube into the filler neck down into the vent opening and gently blow out diesel fuel that may be trapped in a low spot. If it blows back at you that means a restriction somewhere in the vent system. Absolutely no fun fueling for a half hour!
        Hope this helps, Fred
Title: Re: Fuel filler tube problem
Post by: Paul Schwalen on July 03, 2015, 07:18:02 PM
Let me chime in here.  I have a 03’ Contessa with fuel ports on both sides.  We have had this RV for 8 years and I have always had a problem when trying to get the tank full. 
I have fashioned a wooden wedge that I have covered with rubber so it will not slip and use it to hold the pump valve open at a lower setting than the lowest notch on the pump handle.  This does not make the process faster but I don’t have to stand there holding the nozzle on.  This still allows the nozzle to turn off when the fuel comes up the filler tube.
What Gerald said about the location of the fuel filler hose into the tanks describes what I have (approx. 1/3 of the way down from the top of the tank).  Interestingly enough in these 8 years I have never noticed the location of the vents inside the filler tube as described by Fred. 
I found a pc of aquarium hose and applied compressed air and the diesel fuel rises up from the filler hose on both sides.  I am not a plumber but to me that would indicate the vents are clear.  Since my tank is now essentially full it came up the hose quite fast.
The few times I have added fuel when the tank was low in fuel (perhaps ¼ full) I was able to use the lowest setting on the high pressure pumps but only for a short time until the fuel rises above the entrance level into the tank and then it shuts down and I resort to the wedge system.
I find it much easier to fill up at FJ’s that have RV islands or Sams Clubs where the nozzles are not the high pressure ones at the truck stops.  I have had truckers who were behind me in the que and waiting for me to finish that yell and honk for me to get out of their way because of the time it takes me to fill with the high pressure nozzle.
Thanks to Fred for his suggestion on how to test the vents for blockage.

Title: Re: Fuel filler tube problem
Post by: Gerald Farris on July 03, 2015, 09:24:22 PM
On the single filler neck coaches, almost all of them run the vent hose to the top of the filler neck and do not use a vent check valve in the tank vent system. However, on the dual filler neck coaches most of them run the small hose at the filler neck to the other filler neck and run a vent hose from the top of the tank with a check valve in it, usually at the end, to prevent fuel spills from the vent.

Title: Re: Fuel filler tube problem
Post by: Joel Ashley on July 03, 2015, 11:36:26 PM
I'm not sure this totally relates, but our old gas coach would have problems especially after filling up and hitting the asphalt on hot days.  If the fuel came from cool underground tanks into the warm coach tank, then we drove out onto hot pavement for a short trip and then parked, we could get a strong gas smell.  The small vent line followed the fill tube up to the fill port, and into the metal neck just below the cap.  If you used a non-venting cap that would be a problem, and Fleetwood issued a cap recall at least once that I remember on the thing.

The vent tube was rubber and could fail with age, as could the large fill tube.  On one occasion I found a large sag in the vent, and it had liquid gas in it.  I repaired the tube by splicing new fuel line in (I couldn't access the tank's top, but the old line was good up to the sag) and rerouting the straps they'd used to hold the tube up.  I also added larger hose over things to ameliorate both hoses rubbing on frame members, a preventive fix often used for our Beaver coolant system hoses.

So if you find a dip in your vent line, it could have expanded fuel blocking it if nothing else.  One time I found an oily substance on our concrete pad, and upon examination there was the same stuff on frame members behind the genset.  Noting a narrow tube coming forward from above, I assumed it was the main tank's fuel vent and where the leakage emanated.  Turned out that tube may very well be my fuel vent, but the slow dripping gunk wasn't diesel;  it was from a tech not making sure the genset's filter was snugged up after its initial oil change.  Travel had thrown genset oil back and up.  That's probably not relevant here, except to note where a fuel vent may be on some rigs.  I certainly appreciate Gerald's and Fred's experienced input.

I would add that at Pacific Pride (Pioneer Fuel) outlets I go to, there is usually at least one low speed pump because they cater to all commercial entities, not just big trucks;  company vans and pickups and small church vehicles do business there.  Since there is rarely anyone else or perhaps one other vehicle there, I never feel rushed, don't have to use the high speed pumps if I don't want to, and never hold anyone else up.  It is totally the opposite of the chaos I inevitably encounter at the dreaded Flying J.

Title: Re: Fuel filler tube problem
Post by: Adam Hicklin on July 04, 2015, 04:47:33 AM
I'm home now.  I'll be able to inspect it more closely.  Maybe post some pictures for clarification.  Thanks Fred and Gerald for the direction.

Today I pulled in to Love's to try to top off for the trip home.  It was early so I hoped there wouldn't be the chaos at the truck pumps that Joel and everyone else has experienced.  I was doing good until a guy with a pick up and 5th wheel pulled in behind.  No big deal I thought.  I asked my wife to tell the guy I might be a while and it might be quicker if he backed up and tried another lane. I didn't see that behind the 5th wheel he also had a 20ft boat.  He couldn't back up!  The good news for me and bad news for him is that it ONLY took about 30 minutes to get 50 gallons..
Title: Re: Fuel filler tube problem
Post by: Jerry Emert on July 04, 2015, 04:12:00 PM
Happy 4th y'all!  You guys have got me thinking as usual, which has led me to crawling around under the coach in the RV Park we are camped at.  My wife thinks I'm crazy.  They are all at the pool and I'm under the coach looking for fuel filler pipes!  Anyway, I have fillers on both sides of the coach.  The hose that goes to the tank on the Stbd side enters it about 18 inches or so up from the bottom.  No kinks on that side and no vent anywhere that I can see.  The port side is about the same but I can't see it very well because of the way my tires are turned.  I guess my question is, just what are some other vent location options?  Ideas??  Thanks.
PS I can usually fill at a reasonable rate if I turn the nozzle just right at a reg. gas station type pump.  High speed pumps are a complete pain.  Both sides are the same.
Title: Re: Fuel filler tube problem
Post by: Fred Brooks on July 04, 2015, 04:33:51 PM
           Hi Jerry,

    What a Great Country the Lord has blessed us with, hope it stays that way! I have only had my coach 10 months and still in a serious learning curve. I guess i'm one of the lucky owners when it comes to fueling. I remove both fuel caps and can normally put the pump on the slow fill clicker and wait. It does slow down towards the end when I try to top off. Most tank manufacturers want that 10 percent air space in the top of the tank but not real sure why. Perhaps for the roll over safety vent? When your done hope you enjoy the pool.

        Regards, Fred
Title: Re: Fuel filler tube problem
Post by: Al Lewis on July 10, 2015, 09:33:50 PM
My 2002 Monterey has the same problem. I concluded the vent hose had low spots that acted as p traps. I did my best to eliminate the low spots. Now the best I can do is fill on drivers side, carefully position the nozzle,set truck nozzle on first notch. About 20 minutes for 60 gallons. At least the truckers are not honking at me. I wish they had put the filler tube in the top of the tank rather than down closer to the bottom.