Fumes from built in gas tank normal?

[craptacular]

Hi all, is it normal for the build in gas tanks to have a bit of fumes in the lower compartment? Its noticeable but not overpowering. I don't notice any gas leaking but was wondering if this is normal...since I believe its an open vent all the time. Hoses look ok from what I can see but haven't torn the floor up.

[REW]

If you can smell gas vapors, you have a potential fire and explosion situation.
No, it is not normal, and don't let anyone tell you that it is all right.
You are talking about your life and the lives of those about who you care.

The one thing to verify - where is the vent on your boat.

Sometimes, in some boats, and with some boat covers, the boat cover covers the vent in the boat. If that is the case, change the cover so that the vent is not covered.

When the temperature rises, the gasoline needs to evaporate. As a result, there will be vapors coming from the fuel tank. You need to make sure that if this happens, and it will, that the vapors are not trapped anywhere in the boat, under a cover, under a floor, under a hatch.

If you don't find issues there, you need to search out the source of your fumes. You may have a hole that is porous enough to leak fumes, you may have a loose clamp, you may even have a fuel tank that is leaking fumes.

What ever the case- eliminate the fumes and you will eliminate the potential source of fire and explosion.

It seems that there have been some brands and or models of boats that have a reputation for fume build up, and the owners and or dealers say that this is all right.
I suppose that if you don't value your life or those of y our friends and relatives who may be on the boat, then it is all right. Otherwise, NOT.

Be safe and fume free.

Take care
REW

[wiredog]

If your boat has a plastic tank it is normal. The gas fumes permate thru the plastic walls of the tank. Wiredog

[fireboat]

Originally Posted by craptacular

Hi all, is it normal for the build in gas tanks to have a bit of fumes in the lower compartment? Its noticeable but not overpowering. I don't notice any gas leaking but was wondering if this is normal...since I believe its an open vent all the time. Hoses look ok from what I can see but haven't torn the floor up.

Do a search on this site and you will learn that poly gas tanks DO permeate fumes. Also search a post from "Hot Runr Guy", he did an excellent job of explaining what's happening with the poly tanks. You mentioned you had "a bit of fumes" not a bad gas smell. I found this on line, The odor threshold of gasoline (i.e. , the lowest concentration that an average person can detect by smell), is 0.25 PPM in air. The lowest concentration that gasoline is explosive is 1.4% = 140,000PPM. So the concentration that it is explosive is 560,000 X greater than it was first observed. Gasoline is very detectible even at low concentrations that are not flammable. If you think you have a leak, find it and fix it. My lawn mower, grass trimmer, snow blower, all have a slight gas smell, all have poly tanks, all are in my garage, none have blown up.

[craptacular]

Originally Posted by fireboat

Do a search on this site and you will learn that poly gas tanks DO permeate fumes. Also search a post from "Hot Runr Guy", he did an excellent job of explaining what's happening with the poly tanks. You mentioned you had "a bit of fumes" not a bad gas smell. I found this on line, The odor threshold of gasoline (i.e. , the lowest concentration that an average person can detect by smell), is 0.25 PPM in air. The lowest concentration that gasoline is explosive is 1.4% = 140,000PPM. So the concentration that it is explosive is 560,000 X greater than it was first observed. Gasoline is very detectible even at low concentrations that are not flammable. If you think you have a leak, find it and fix it. My lawn mower, grass trimmer, snow blower, all have a slight gas smell, all have poly tanks, all are in my garage, none have blown up.

Thanks for the heads up. I found this:

"yeah, what he said. Some light reading on the subject:
http://www.moellermarine.com/sites/m...ller_Sheet.pdf

http://www.factoryrvsurplus.com/prod...below_deck.pdf (page #5)

HRG "

I can't see any leaks or signs of gas, everything looks tight. But will try and pull floor to double check.

The tank seems to have 3 hoses connected to it - 2 go to filler (1 vent, 1 filler) and the other goes to the motor.