fuel tank venting

I have a cyclone 3950 and was wondering where the vent is located on the aux tank. when I use the pump to fill a tank I have to loosen the cap to get fuel to pump. I then hear the tank pop back into shape as though the pump was creating a vacuum.
 

avvidclif

Well-known member
On mine I have to do the same. Due to EPA it has a minscule vent and works Ok for the generator but a larger volume of gas creates a problem. I just loosen the cap and fill the tanks.
 

oscar

Well-known member
My problem is filling up. Not sure what the EPA has to do with this, but you have to VERY carefully filling it, so it doesn't slosh back and spill. Takes about 15 minutes to get 20 gallons in there. Right.
 

IronJ

Well-known member
I had a similar issue recently with my aux tank popping with temp change...seems like no venting at all...

But I can pump from it just fine?? And no issues pumping in either?

sent from space via an invisible beam from a flying metal dish
 

porthole

Retired
The factory caps don't seem to be vented.

I have to loosen the cap if I am using the nozzle, but the genny uses little enough that the venting does not seem to be an issue.
As to putting fuel in, if you look at the level of the tank, and the level of the inlet it is easy to see why there can be splash back. That is also the reason it is very difficult to put fuel in using 5 gallon jugs.

Other brand toy haulers had the fill pipe much higher, and the pipe came up through the garage floor and was trimmed to be hidden, but it took up garage space.
The early Cyclones advertised no impingement into the garage area with the fuel fill.

So it is a trade off. Open floor in the garage and a low entry pipe or a bump out in you garage to trip over or get in the way.
The first toy hauler I looked at to buy had the bump outs, seeing those I prefer the flat floor.
 
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