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 a genuine OEM replacement part, it is sold individually.
The purpose of the filter is to keep dust and debris from contaminating the carburetor and engine.

To replace the filter you can place it in a plastic bag with a little oil and rub the oil into the filter.
Then remove the filter and squeeze it in a paper towel to remove the excess oil.

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.

This is a genuine Ruixing replacement part, it is sold individually.
By pressing the bulb, it will purge the carburetor of air.
Fuel will be forced up from the fuel tank through the fuel line then into the carburetor.
Then the excess fuel will be forced back into the fuel tank through the fuel return line.

At some time the primer will lose its elasticity or crack and need to be replaced.

We have an article and video on How to Replace a Primer Bulb, in our Repair Center. That can be found on the front page of our site.

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.

A carburetor basically consists of an open pipe through which the air passes into the inlet manifold of the engine.
The pipe is in the form of a Venturi: it narrows in section and then widens again, causing the airflow to increase in speed in the narrowest part.
Below the Venturi is a butterfly valve called the throttle valve — a rotating disc that can be turned end-on to the airflow, so as to hardly restrict the flow at all, or can be rotated so that it (almost) completely blocks the flow of air.
This valve controls the flow of air through the carburetor throat and thus the quantity of air/fuel mixture the system will deliver, thereby regulating engine power and speed. The throttle is connected, usually through a cable or a mechanical linkage of rods and joints.

Fuel is introduced into the air stream through small holes at the narrowest part of the Venturi and at other places where pressure will be lowered when not running on full throttle.