Because a battery gives off hydrogen gas when it is charging and discharging. Be careful not to create sparks around a battery especially when jumpering because hydrogen is volitile.
to avoid accumulation of hydrogen gases near battry
There is no reason at all for you to remove the factory plug. The battery will vent just fine.
Check the vent tube for the fuel tank. If it is pinched it will cause that condition. Not knowing what vehicle you have, some vent tubes are located inside the filler neck and not visible unless you remove the filler neck from the tank.
Filler neck and vent pipe in the yard is one clue.
The vent is blocked for some reason. Has the fuel tank been removed recently? If so, someone installed the filler/vent hose incorrectly.
No, that will have no effect on the battery.
Changing spark plugs is an easy task. Disconnect the battery, disconnect the cables, remove the old spark plugs, put in the new spark plugs, reconnect the cables, and reconnect the battery.
no.
The fuel tank vent is blocked, pinched off or disconnected.
Try replacing oil filler cap.
Replacing spark plugs is pretty simple. Disconnect the battery and the spark plug cables, and remove the old spark plugs. Put in the new spark plugs, reconnect the cables and the battery.
If an auto transaxle, the filler tube is on the left side of the engine (from front) tust under the battery tray, down close to the fenderwell. It has a a pull-out dipstick. The dain plug is under the engine on the back side of the t-a housing. If a manual t-a, the filler and drain plugs are both on the bottom side of the t-a housing. The lower point is the drain and the upper plug is the filler. A squeeze-type container will be required to fill if an electric or pump-type is ot available.