Community Forums

lowellvahl · 05-31-2017, 12:19 PM

We recently purchased a 2003 Safari Zanzibar 3922 (Roadmaster Chassis with Cummins ISL 370) and filling up is painfully slow. It will pump in 7 gallons and click off and then click off every 1/2 gallon after that.
I found what I thought was a 1/2" vent tube running from the tank along the filler tube and ending right below the cap on the filler tube. It had a slight sag (8 inches) so I zip tied it closer to the tube, but that did not change anything.
Is there another vent hose that I am missing? I did not see any hoses around the tank cut off or just hanging down. Anyone had this issue before and know what else might be causing the problem?

Lowell

windsorbill · 05-31-2017, 12:42 PM

My tank fill is about a 2" pipe. It's not like a car where there is a small fairly tight area for the pump nozzle to fit into.

So when my tank is filling, I doubt it is using the vent line at all. It vents through the fill pipe, especially when I use the high volume pumps at many large truck stops. My vent line is only being used when the caps are on the tank and the engine is sucking fuel.

If you have a large fill pipe like mine, there could be something else going on besides a venting issue.

lowellvahl · 05-31-2017, 01:38 PM

Mine is also about a 2" fill pipe, so what you are saying make sense too. I am just not sure where to start trouble shooting on this problem. I will crawl under it again and see if there might be something else I can find.
thanks

windsorbill · 05-31-2017, 03:28 PM

Does your fill pipe go directly into the tank or is there a hose connected to it? If you have a hose and is somewhat horizontal, that will allow fuel to back up enough to trip the fuel nozzle off.

Playtime III · 05-31-2017, 03:53 PM

Mine has a vent line near the middle of the tank, running to the bottom of the coach. My issue was different, when I opened either fill cap, I would get a whoosh sound. My vent line was plugged by muddaubers.

lowellvahl · 05-31-2017, 07:57 PM

Quote:

Originally Posted by windsorbill

Does your fill pipe go directly into the tank or is there a hose connected to it? If you have a hose and is somewhat horizontal, that will allow fuel to back up enough to trip the fuel nozzle off.

I looked at it again this afternoon. The filler tube is at least 2" and runs all the way to the fuel tank entering the tank on the front side about 3/4 of the way to the top. The 1/2" vent hose does enter right at the top front of the tank. It does seem odd that the filler hose is not entering at the top of the tank, but it all looks original and I cannot see any sagging in the filler hose.

lowellvahl · 05-31-2017, 07:59 PM

Quote:

Originally Posted by Playtime III

Mine has a vent line near the middle of the tank, running to the bottom of the coach. My issue was different, when I opened either fill cap, I would get a whoosh sound. My vent line was plugged by muddaubers.

I cannot see a vent hose hanging down on either side of the tank and did not hear a whoosh sound opening the cap. I had read your earlier post about the plugged vent line so that is the first thing I looked for.
Lowelll

windsorbill · 05-31-2017, 08:00 PM

Quote:

Originally Posted by Playtime III

Mine has a vent line near the middle of the tank, running to the bottom of the coach. My issue was different, when I opened either fill cap, I would get a whoosh sound. My vent line was plugged by muddaubers.

those suckers get in everywhere.

I rented a inexpensive class C motorhome years ago. It was a gasser but was having same issue as the OP. The filler tube was almost horizontal and while filing up, the gas would keep tripping the auto shut off. Took forever to put in 30 or 40 gallons of gas. Very frustrating.

I complained when I returned it. I doubt they did anything about it.

lowellvahl · 06-01-2017, 10:31 AM

Quote:

Originally Posted by windsorbill

those suckers get in everywhere.

I rented a inexpensive class C motorhome years ago. It was a gasser but was having same issue as the OP. The filler tube was almost horizontal and while filing up, the gas would keep tripping the auto shut off. Took forever to put in 30 or 40 gallons of gas. Very frustrating.

I complained when I returned it. I doubt they did anything about it.

With the filler hose connecting several inches below the top of the tank, I started thinking that it may be an issue I will have filling the top 1/4 of the tank. In thinking about the few times it filled, it was always nearly 1/2 full when I was topping it off. I probably should try to run it down to 1/4 tank and see if it fills the first 25 gallons (88 gallon capacity) before it clicks off.
Or another option might be to put a "T" in the existing vent above the tank line to make sure it is getting plenty of air vented out.
Lowell