The 308181004 Fuel Tank is an OEM replacement part.
It is compatible with the models shown below.
It includes the fuel lines, fuel cap and fuel filter.
If you need to order the fuel tank bumpers, they are sold individually as part number 98792.

This is an OEM replacement part.
It has a right hand thread screw to remove and attach it to the trimmer head.

Its purpose is to hold the spool with the cutting line, in the spool housing.
It also acts as the bumper to advance the line from the spool.

This is a well used and abused part of the trimmer.
It may be a good idea to order an extra one.

The 791-682039 Fuel Filter and Line, filters the fuel in the tank as it is forced into the carburetor up by means of the primer bulb.

To install.
Remove retainer ring from fuel line.
Insert fuel line thru gas cap opening.
Thread fuel line thru hole in bottom of the fuel tank.
Pull fuel line thru to firmly seat against inside tank wall.
Put retainer ring on fuel line,hold line and press ring firmly against the out side of the fuel tank wall.
Then attach fuel line to correct line on the carburetor.

The filter will at sometime get clogged with dirt and debris that has collected in the fuel tank, and will have to be replaced.

The primer hose is inserted into the fuel tank then connected to the Primer.
By pressing on the primmer a few times this assembly fills the carburetor with fuel.
When the carburetor has enough fuel in it, the excess fuel is forced back into the the tank through the fuel return line.

After time the primer hose will become brittle and crack and have to be replaced.
The primer will also lose its elasticity, and may also crack and not be able to suck up the fuel into the carburetor.
And will have to be replaced.

The purpose of the 791-181086 Fuel Return Tube is to return the excess fuel back into the fuel tank, after the primer bulb has been pressed and has primed the carburetor to start.

After time the Fuel Return Line will become brittle and crack and will need to be replaced.

This is an OEM replacement part,it is sold individually.
The purpose of the Air Purge Bulb is to purge all of the air from the carburetor.
It then brings fuel up through the fuel line in the tank into the carburetor.
Once the carburetor is full of fuel the Bulb will force the excess fuel back into the tank through the fuel return line.

Over time the bulb will loose it elasticity or begin to crack, it will need to be replaced at this time.