Carburetor HOMELITE CSP4518 Ryobi RY10518 RY10519 RY10520 RY10521

This Homelite CSP4518 carburetor – a non-original replacement part for the Homelite and Ryobi petrol chain saws listed below. It is used on the 45 cm³ Homelite CSP4518 and related 46 cm³ Ryobi saw families.

In the Homelite CSP4518 factory parts list the carburetor assembly is listed under number 308070001. In the Ryobi RY10519 and RY10521 family parts catalogs the later carburetor number is 309360002.

Homelite CSP4518 Carburetor Compatibility

Fits the following chain saws:

Homelite CSP4518
45 cm³ engine
18-inch cutting bar model
Type UT74125A
Type UT74125D
Ryobi RY10518
46 cm³ engine
18-inch cutting bar model
Ryobi RY10519
46 cm³ engine
18-inch cutting bar model
Ryobi RY10520
46 cm³ engine
20-inch cutting bar model
Ryobi RY10521
46 cm³ engine
20-inch cutting bar model

Also fits these documented Ryobi versions:

Ryobi RY10519A
Ryobi RY10521A
Ryobi RY10519B
Ryobi RY10521B

The letters A and B denote later RY10519 and RY10521 saw versions. Their factory repair parts lists indicate the carburetor assembly 309360002.

Carburetor Numbers

Key factory numbers:

Homelite CSP4518 carburetor assembly: 308070001
Ryobi RY10519 \/ RY10521 carburetor assembly: 309360002

These numbers are used across different iterations of the related saw platform. Therefore, when selecting a part it is essential to check the specific saw model.

The item for sale is the non-original carburetor shown in the product photos. Intake gaskets, fuel lines, filters and external linkages are separate parts if they are not shown together with the sold carburetor.

What to Check Before Installing?

Before removing the old carburetor, photograph or mark:

Location of the fuel supply line
Location of the fuel pump return line
Throttle linkage position
Choke linkage position
Intake gasket orientation

Compare the mounting holes, intake port, fuel connections and control levers of the old and new carburetors.

When disassembling, inspect the intake connector, carburetor adapter, adapter seal and carburetor gasket. In the CSP4518 parts catalog these are listed as separate sealing parts. In the Ryobi repair diagram the adapter, seal and gasket are also shown separately.

Once mounted, but before reinstalling the external covers, check the throttle operation by hand. The throttle must open fully and return freely to the idle position.

Finally, check all fuel connections and ensure there are no leaks. Adjust idle and fuel mixture according to the repair specifications for the specific Homelite or Ryobi model.

You can find more compatible parts in the Homelite CSP4518 parts category.