Gas cap venting?

[PUP300]

New boat owner and wish to ask a few questions regarding the fuel tank. I have a 6 gal. portable plastic fuel tank with a venting screw on the cap.

1. When should the vent be closed and when should it be open? (I do know it needs to be open while engine is running) I was wondering as far as trailering and sitting in the garage.

2. Should the tank be removed from the boat when sitting in the garage while in season?

3. Is size of gas tank relate to size of motor?

4. Last one, is there a aftermarket cap for a portable fuel tank that has automatic venting?

Thanks in advance.

Paul

 

[JB]

Re: Gas cap venting?

1. I would keep it closed except when running or preparing to run the engine.

2. I see no reason to remove it.

3. No. I have used 3gal tanks with 70s and a 28gal tank with a kicker. Tank size should match the amount of fuel you might use on one trip, regardless of engine size.

4. There might be, but I am not aware of it.

 

[OptsyEagle]

Re: Gas cap venting?

The problem I experience when keeping the vent closed during storage is with the plastic tanks, a change in the temperature (usually going colder at night) squishes the tank like a pancake. I don't know if this hurts it or not but it doesn't look good for it.

How do people deal with that?

 

[Woodnaut]

Re: Gas cap venting?

JB's got all the right answers. (As usual.) If it's a plastic tank, keeping it full while storing it will eliminate its collapse which is caused by contraction of the air when cooler temperatures hit. I would suggest keeping it mostly full with the vent closed when not in use. If you store it empty, then leaving the vent open will prevent it from collapsing, but it will also pull in a little air and humidity.

On this forum you'll find lots of dicussions about what is best for storage: tank-empty or tank-full. Rather than ignite this topic I'll just say that I trailer my boat and I've not had any problems with condensation in either built in tanks nor with with 6 gallon portables. However, I always use a fuel stabilizer/additive - and that's one thing that everyone can agree upon.

I have (inadvertently) collapsed plastic tanks before, and although they seem to have survived, I can't imagine that it is good for them. It seems that if this was does enough times that a failure will eventually occur.

 

[pecheux]

Re: Gas cap venting?

I left my boat outside under the sun while working in the garage ... forgot to open the vent screw on the tank .. result after a while the tank looked like a giant football.

The gas hose was connected to the motor = engine needed a carb job from too much pressure from the tank.

The vent is now open as soon as the boat leaves the shade from it's storage place.

 

[mthieme]

Re: Gas cap venting?

1. I would keep it closed except when running or preparing to run the engine.

2. I see no reason to remove it.

3. No. I have used 3gal tanks with 70s and a 28gal tank with a kicker. Tank size should match the amount of fuel you might use on one trip, regardless of engine size.

4. There might be, but I am not aware of it.

I agree with JB, except I don't store any flammables in my garage due to the fact that it is my shop and I heat it with a wood stove. I have a shed at the far corner of the property which stores that kinda stuff.
Ihave never seen an automatic vented cap.

 

[PUP300]

Re: Gas cap venting?

JB's got all the right answers. (As usual.) If it's a plastic tank, keeping it full while storing it will eliminate its collapse which is caused by contraction of the air when cooler temperatures hit. I would suggest keeping it mostly full with the vent closed when not in use. If you store it empty, then leaving the vent open will prevent it from collapsing, but it will also pull in a little air and humidity.

On this forum you'll find lots of discussions about what is best for storage: tank-empty or tank-full. Rather than ignite this topic I'll just say that I trailer my boat and I've not had any problems with condensation in either built in tanks nor with with 6 gallon portables. However, I always use a fuel stabilizer/additive - and that's one thing that everyone can agree upon.

I have (inadvertently) collapsed plastic tanks before, and although they seem to have survived, I can't imagine that it is good for them. It seems that if this was does enough times that a failure will eventually occur.

Woodnaut - thank you and thanks to all others the have replied. I know what you mean about re-hashing gas storage. I have seen many topics on that, this is why I put in season while sitting in the garage. I was wondering what you guys do, because I am having issues with my tank pressurizing and de-pressurizing while sitting in my garage between outings. I try to keep the vent open but feel it may be un-safe. The tank itself is actually over half full. I guess I will have to release daily, unless you guys know of an automatic vent that I can add or possible cap with auto vent.

Thanks again!

Paul

 

[Calhere]

Re: Gas cap venting?

The vent should be open anytime it is not shaded or if it is in direct sunlight otherwise it could cause the tank to expand and this may lead to replacing the tank because of continued leaking I found that out the hard way!