Ryobi 4545 Chainsaw Manual

The Ryobi 4545 is a 45cc gas-powered chainsaw designed for medium-duty cutting tasks such as limbing, pruning, and felling small to medium trees. It features a 2-stroke engine, automatic oiler, anti-vibration system, chain brake, and a 16-inch Oregon bar and chain. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Assembly & Preparation 3. First-Time Operation 4. Specifications 5. Controls and Functions 6. Fuel & Lubrication 7. Cutting Techniques 8. Safety Features 10. Maintenance & Storage 11. Regulatory Information 12. Troubleshooting

Features at a Glance

Key components: 45cc 2-stroke engine, 16-inch Oregon bar and chain, automatic chain oiler, inertia-activated chain brake, anti-vibration handles, decompression valve, primer bulb, and side-access chain tensioner.

Feature	Description
Engine Displacement	45cc 2-stroke air-cooled engine
Bar Length	16 inches (Oregon)
Chain Oil	Automatic oiler with manual override
Safety Features	Inertia-activated chain brake, hand guard
Vibration Reduction	Anti-vibration system in handles
Starting System	Decompression valve, primer bulb
Chain Tensioning	Side-access tool-less tensioner
Fuel Capacity	Approx. 14 oz (414 ml) tank
Oil Capacity	Approx. 8 oz (237 ml) reservoir
Weight	10.8 lbs (4.9 kg) without fuel/oil

Assembly & Preparation

Unpack and inspect all parts. Assemble on a clean, flat surface.

Attach the guide bar and chain: Loosen bar nuts, position chain on bar, align bar with sprocket, tighten nuts finger-tight.
Adjust chain tension: Use side tensioner to set proper tension (chain should snap back when pulled).
Fill with fuel: Mix 50:1 gasoline and 2-stroke oil (89 octane minimum).
Fill chain oil: Use bar and chain oil only.

WARNING! Always wear cut-resistant gloves during assembly. Ensure chain is installed with cutting teeth facing forward.

First-Time Operation

Before starting, review all safety instructions.

Place on ground: Firm, level surface, clear of debris.
Engage chain brake: Push forward until click.
Set choke: Move to FULL position for cold start.
Prime: Press primer bulb 5-6 times.
Pull starter: Hold front handle, pull cord until engine fires.
Disengage choke: Move to RUN position.
Release chain brake: Pull back toward handle.

CAUTION! Never drop-start or start above waist height. Keep bystanders 15 feet away.

Specifications

Engine: 45cc 2-stroke, air-cooled.
Fuel: 50:1 gas/oil mix (89 octane).
Bar: 16-inch Oregon, .325 pitch.
Chain: Oregon 72 drive links.
Oiling: Automatic with manual override.
Safety: Inertia chain brake, throttle lockout.
Weight: 10.8 lbs (dry).
Sound Level: 105 dB(A) at operator's ear.
Vibration: <2.5 m/s² per ISO 5349.

Controls and Functions

Main controls: Throttle trigger, throttle lockout, choke lever, primer bulb, decompression valve, chain brake, master control lever.

Right Side: Throttle trigger (requires lockout to be pressed), chain brake handle, choke lever. Left Side: Decompression valve, primer bulb, oil fill cap. Rear: Fuel cap, master control lever (combines choke/stop functions).

Operation: Press throttle lockout, then squeeze trigger to increase RPM. Push chain brake forward to engage (safety stop). Pull back to disengage for cutting.

Fuel & Lubrication

Fuel: 50:1 mix (2.6 oz oil per gallon). Use fresh gasoline (<30 days old). Chain Oil: Bar and chain oil only (not motor oil).

Fill fuel: Clean area, use funnel, avoid spills.
Fill oil: Check level before each use.
Check oil flow: Run at high idle, look for oil line on ground.

Tip: Store fuel in approved container. Never refuel while engine is hot.

Cutting Techniques

Basic cuts: felling, limbing, bucking.

Felling: Plan escape path, make notch cut, then back cut.
Limbing: Stand uphill, cut from trunk outward.
Bucking: Support log, cut from top, avoid pinching.
Kickback prevention: Keep nose out of cut, maintain firm grip.
Pinch release: Use wedges, never force bar.

WARNING! Always cut at full throttle. Never cut above shoulder height. Beware of kickback zone (upper quarter of bar tip).

Safety Features

Chain Brake: Inertia-activated; stops chain in 0.15 sec if kickback occurs. Throttle Lockout: Prevents accidental throttle engagement. Hand Guard: Protects from debris. Anti-Vibration: Reduces fatigue.

Maintenance & Storage

Daily: Clean air filter, check chain tension, sharpen chain. Monthly: Clean spark arrestor, check spark plug. Storage: Run dry, remove chain, clean whole unit, store in dry place.

CAUTION! Disconnect spark plug before maintenance. Use only genuine Ryobi parts.

Regulatory Information

EPA/CARB compliant. Meets ANSI B175.1 safety standards. Contains FCC Part 15 Subpart B compliant ignition system. Copyright © Ryobi Limited. For support, visit www.ryobitools.com or contact 1-800-525-2579.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Old fuel, clogged filter, no spark	Use fresh mix, clean filter, check spark plug gap (0.025").
Engine runs then dies	Fuel line, carburetor, vent	Check fuel lines, clean carb, ensure tank vent is open.
Chain doesn't oil	Empty reservoir, clogged port	Fill oil, clean oil ports, check pump operation.
Chain comes off bar	Loose bar nuts, worn bar	Tighten nuts, inspect bar rails, replace if worn.
Excessive vibration	Loose parts, damaged AV mounts	Tighten all fasteners, inspect anti-vibration mounts.

Service: 1-800-525-2579; www.ryobitools.com