Petrol chainsaw oil pump HomeLite 4518

This Homelite CSP4518 oil pump – a Winzor non-original chain lubrication system pump, designed for compatible Homelite and Ryobi petrol chain saws. In the original CSP4518 parts list the oil pump assembly is listed under number 300945001.

In later parts catalogs and in Ryobi's original parts systems the same pump family is also assigned numbers 300945002 and 5131000552. In Homelite parts systems the older number 300945001 is also associated with PA01396.

Compatible Homelite and Ryobi Models

Main models:

Homelite CSP4518
Homelite CSP4520
Homelite CSP4016
Ryobi PCN4040
Ryobi PCN4545

The same oil pump family is also catalogued as:

Homelite CSP3314
Homelite CSP3316
Homelite CSP4513
Ryobi HCS3335
Ryobi PCN3335
Ryobi RCS3335
Ryobi RCS5133

Choose the part according to the specific saw model and pump number. Engine displacement alone is not sufficient, because this oil pump family is used on engines of different displacements.

Homelite CSP4518 Technical Data

The Homelite user manual states:

Model: CSP4518
Type number: UT74125A \/ UT74125D
Engine displacement: 45 cm³
Pjovimo juostos ilgis: 457 mm \/ 18 colių

The related CSP4520 model is specified as:

Model: CSP4520
Type number: UT74127A \/ UT74127D
Engine displacement: 45 cm³
Pjovimo juostos ilgis: 508 mm \/ 20 colių

These data describe the chainsaws themselves and should not be used as a universal specification for oil pump dimensions.

Oil Pump Numbers

Important part numbers:

Previous oil pump assembly: 300945001
Later oil pump number: 300945002
Ryobi original replacement number: 5131000552
Homelite replacement number: PA01396

In the earlier CSP4518 factory parts list the oil pump was marked 300945001.

In a later CSP4518 parts diagram the oil pump assembly uses the number 300945002. In Ryobi's original parts system 300945001, 300945002 and 5131000552 are presented as interrelated numbers.

For this reason, when searching for a part across catalogs from different years you may find multiple numbers for the same pump application.

CSP4518 Chain Lubrication System Parts

The CSP4518 lubrication system consists of more than just the pump itself.

The parts catalogs list the following related parts:

Oil pump: 300945001 \/ 300945002
Oil outlet sleeve: 570226001
Oil pickup tube with filter listed in an earlier catalog: 300950001
Oil pump worm gear listed in a later diagram: 610389001

It's worth checking these parts before replacing the pump.

A new oil pump will not solve lubrication problems if the oil pickup system is clogged, the outlet channel is blocked or the worm gear driving the pump is worn.

Symptoms of Lubrication System Failure

The lubrication system should be checked if:

The bar and chain remain dry during operation
The chain gets unusually hot
The oil level in the tank barely decreases when using the saw
Oil does not reach the bar's oiling hole
The bar wears quickly even though the correct chain oil is used

First remove the bar and clean its oiling hole and groove. Then check the saw's oil outlet channel, the oil pickup system and the pump drive.

Installation and Inspection

Remove the clutch and surrounding parts according to the specific chainsaw repair procedure. When the oil pump is accessible, also inspect its worm gear.

Before installing a new pump remove hardened oil, sawdust and other contaminants from the pump area and oil channels.

After reassembly fill the tank with oil intended for chains and bars. Start the engine safely and before you start cutting check that oil is reaching the bar feed point.

Find more suitable engine, clutch and lubrication system parts in the Homelite CSP4518 parts category.