Remote breather for petrol tank

[chris-s]

if I was to fit a remote fuel tank in the sole locker for our petrol outboard rather than use the one built into the engine, I would fit a remote breather vent. Would I need a shutoff tap in the breather line?

Chris

 

[fredrussell]

If you mean one of the red plastic purpose built tanks they always have a breather device built into them - usually in the form of a simple screw fitting that you open when you start engine and then close when you stop engine.

 

[VicS]

if I was to fit a remote fuel tank in the sole locker for our petrol outboard rather than use the one built into the engine, I would fit a remote breather vent. Would I need a shutoff tap in the breather line?

Chris

Unless the tank is removable for filling you will also need a deck filler. I would not fit a valve in the vent of a prmanently installed tank.

If it will be removable for filling you need either a valve and an easily detachable vent line or a connector which automatically closes when the vent line is detached. Something like the fitting for a detachable fuel line on an outboard tank

Often thought bout doing something similar but never got as far as researching the detail.

( I Assume your outboard has the facility to connect a remote tank and a fuel pump capable of drawing fuel from it.)

 

[chris-s]

Thanks guys. Yes I will remove the tank for filling to avoid vapour in the bilges and yes the Yamaha engine has both built in tank and external input.

I was going to fit the vent to the cap and I have a spare cap for use when taking the tank for filling.

I was trying to work out whether I need a shutoff to close when leaving the boat to avoid all my petrol evaporating away.

Chris

 

[lw395]

Many motorcycles use a little one way valve to let air into the tank without letting vapour or fuel out.

 

[VicS]

Thanks guys. Yes I will remove the tank for filling to avoid vapour in the bilges and yes the Yamaha engine has both built in tank and external input.

I was going to fit the vent to the cap and I have a spare cap for use when taking the tank for filling.

I was trying to work out whether I need a shutoff to close when leaving the boat to avoid all my petrol evaporating away.

Chris

You could always fit the spare cap.

 

[prv]

You could always fit the spare cap.

A small brass or plastic ball valve on the vent line would be easier than swapping the cap on a full tank below the sole boards in a seaway, and the cost is trivial, so it seems like a perfectly reasonable question to me. I don’t know the answer though - portable tanks always have closeable vents, but I’ve never heard of manually opening and closing the breathers on RIBs and other boats with large inbuilt petrol tanks.

I’m inclined to guess that it’s not necessary but wouldn’t hurt, and you might get the odd whiff of petrol smell in the cockpit without it which would be nice to prevent.

Pete

 

[VicS]

A small brass or plastic ball valve on the vent line would be easier than swapping the cap on a full tank below the sole boards in a seaway, and the cost is trivial, so it seems like a perfectly reasonable question to me. I don’t know the answer though - portable tanks always have closeable vents, but I’ve never heard of manually opening and closing the breathers on RIBs and other boats with large inbuilt petrol tanks.

I’m inclined to guess that it’s not necessary but wouldn’t hurt, and you might get the odd whiff of petrol smell in the cockpit without it which would be nice to prevent.

Pete

The was only considering closing a vent when leaving the boat,

I suspect, as you do that it is not necessary but if he is able to fit a cab it gives him the opportunity to determine if closing the vent is desirable or not before

 

[William_H]

OP might be better off trying to seal the locker from the cabin if it is not already. Then as I have a slot in the lid of the locker to allow the hose to come out which will provide some ventilation of fumes if that is a concern. Then just rely on the vent on the tank. Perhaps a good idea to seal off when you leave the boat but then you probably will take the tank away anyway. So no need for a remote vent line. ol'will