Gas Line Trimmer

Model # 990R Official Ryobi string trimmer

Here are the diagrams and repair parts for Official Ryobi 990R string trimmer, as well as links to manuals and error code tables, if available.

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Browse Parts for
990R Line Trimmers
Screw 683304
#10

Lower boom & cutting head diagram

Screw

Part #683304

The manufacturer no longer makes this part, and there's no substitute part

Block 181042

#NI

All parts diagram

Block

Part #181042

The manufacturer no longer makes this part, and there's no substitute part

Shaft 181017
#18

Cylinder and crankcase diagram

Shaft

Part #181017

The manufacturer no longer makes this part, and there's no substitute part

Cover 181051
#10

Carburetor and muffler diagram

Cover

Part #181051

The manufacturer no longer makes this part, and there's no substitute part

Cylinder 181041

#NI

All parts diagram

Cylinder

Part #181041

The manufacturer no longer makes this part, and there's no substitute part

Gasket 181048
#7

Carburetor and muffler diagram

Gasket

Part #181048

The manufacturer no longer makes this part, and there's no substitute part

Gasket 181059
#19

Carburetor and muffler diagram

Gasket

Part #181059

The manufacturer no longer makes this part, and there's no substitute part

Screw 181003
Screw

Part #181003

The manufacturer no longer makes this part, and there's no substitute part

Ground Tab 611063
#30

Carburetor and muffler diagram

Ground tab

Part #611063

The manufacturer no longer makes this part, and there's no substitute part

Oil Pan 181019
#20

Cylinder and crankcase diagram

Oil pan

Part #181019

The manufacturer no longer makes this part, and there's no substitute part

Symptoms for gas line trimmers

Choose a symptom to see related grass line trimmer repairs.

Main causes: stale fuel, cracked fuel lines, dirty carburetor, bad spark plug, worn piston rings…

Main causes: stale fuel, clogged fuel filter, faulty spark plug, clogged air filter, cracked fuel lines, clogged carbure…

Main causes: cracked fuel lines, bad carburetor seals, leaky fuel tank cap, damaged fuel tank…

Repair guides for gas line trimmers

These step-by-step repair guides will help you safely fix what’s broken on your grass line trimmer.

How to rebuild a line trimmer carburetor

How to rebuild a line trimmer carburetor

If the line trimmer engine won't start even though there's fuel in the tank, the carburetor could be the problem. Follow…

Repair difficulty
Time required
 15 minutes or less
How to replace a line trimmer carburetor

How to replace a line trimmer carburetor

If the line trimmer won't start even though there's fuel in the tank, the carburetor could be the problem. Follow these …

Repair difficulty
Time required
 15 minutes or less
How to replace a line trimmer fuel line

How to replace a line trimmer fuel line

The fuel line on a grass line trimmer deteriorates with time and eventually can split or crack. You can replace it yours…

Repair difficulty
Time required
 15 minutes or less

Effective articles & videos to help repair your line trimmers

Use the advice and tips in these articles and videos to get the most out of your grass line trimmer.

Straight shaft vs curved shaft trimmers: What’s the difference?

Straight shaft vs curved shaft trimmers: What’s the difference?

Trying to decide between a straight shaft and curved shaft trimmer? This guide compares both designs to help you underst…

Can you cut grass with a weed whacker?

Can you cut grass with a weed whacker?

Wondering if your weed whacker can pick up the slack for your broken lawn mower? You're not alone. In this guide, we bre…