Craftsman 18 42cc Chainsaw Parts Manual

The Craftsman 18 42cc Chainsaw is a gas-powered chainsaw designed for general cutting tasks, featuring an 18-inch guide bar, a 42cc 2-cycle engine, automatic oiling system, chain brake, and anti-vibration handles. This manual provides detailed parts identification, assembly instructions, maintenance procedures, and safety guidelines. Below are key sections for safety, parts list, assembly, operation, maintenance, and troubleshooting.

1. Safety Information 2. Parts Identification 3. Assembly Instructions 4. Specifications 5. Operation Guidelines 6. Maintenance Schedule 7. Chain & Bar Care 8. Carburetor Adjustment 9. Storage Procedures 10. Warranty Information 11. Troubleshooting

Safety Information

Always wear protective gear: safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toed boots. Keep bystanders at a safe distance.

HazardPrecaution
KickbackHold saw firmly with both hands; keep chain sharp; avoid tip contact
Fuel handlingUse fresh fuel mix (50:1); refuel in well-ventilated area away from sparks
Chain contactEngage chain brake when not cutting; keep hands away from moving chain
Electrical hazardsKeep away from power lines; do not operate in wet conditions
Exhaust fumesOperate in well-ventilated area to avoid carbon monoxide poisoning

Parts Identification

Key components: Engine assembly, guide bar, cutting chain, chain brake, throttle trigger, choke control, primer bulb, oil tank, fuel tank, spark plug, air filter, muffler.

  1. Front handle with chain brake lever
  2. Rear handle with throttle trigger
  3. Guide bar (18-inch)
  4. Cutting chain (3/8" pitch, .050" gauge)
  5. Chain tensioning screw
  6. Bar nuts (2)
  7. Clutch cover
  8. Automatic oiler pump
  9. Fuel cap with dipstick
  10. Oil cap

WARNING! Always disconnect spark plug before performing maintenance.

Assembly Instructions

Unpack and inspect all parts. Assembly requires basic tools (screwdriver, wrench).

  1. Attach guide bar: Loosen bar nuts, position bar over studs, align chain with sprocket.
  2. Install chain: Place chain over bar sprocket, ensure cutting teeth face forward.
  3. Tension chain: Adjust tension screw until chain snaps back when pulled from bar.
  4. Secure clutch cover: Tighten bar nuts evenly, recheck chain tension.
  5. Fill tanks: Add fuel mix to fuel tank; add bar & chain oil to oil tank.

CAUTION! Chain must be properly tensioned to prevent derailment or breakage.

Specifications

Operation Guidelines

Starting procedure: Place on flat surface, engage chain brake, set choke, pull starter cord.

Cold Start: Move choke lever to FULL position, press primer bulb 5 times, pull starter cord until engine fires, move choke to HALF, pull until starts, then open choke.

Warm Start: Choke in OPEN position, pull starter cord.

Cutting techniques: Use lower part of bar for cutting; let chain do the work; avoid pinching bar. Always stop engine before moving between cutting locations.

Maintenance Schedule

Daily: Check chain tension, sharpen chain, clean air filter, inspect bar for wear.

Weekly: Clean spark arrestor screen, check fuel lines for cracks.

Monthly: Clean cooling fins, check clutch drum and sprocket.

Seasonally: Replace spark plug, clean carburetor, replace fuel filter.

Tip: Use only genuine Craftsman replacement parts for optimal performance.

Chain & Bar Care

Proper chain maintenance ensures cutting efficiency and safety.

  1. Sharpening: Use round file matching chain pitch; maintain 30° filing angle.
  2. Depth gauges: File depth gauges to .025" below cutting teeth.
  3. Bar maintenance: Clean bar groove weekly; flip bar monthly for even wear.
  4. Lubrication: Always use proper bar & chain oil; check oiler output.

WARNING! Dull chain increases kickback risk and reduces cutting efficiency.

Carburetor Adjustment

Three adjustment screws: L (low speed), H (high speed), T (idle).

  1. Initial settings: Turn L and H screws clockwise until lightly seated, then back out 1-1/4 turns.
  2. Warm up engine: Run at half throttle for 5 minutes.
  3. Adjust idle: Turn T screw until chain stops moving but engine runs smoothly.
  4. Fine tuning: Adjust L for smooth acceleration; adjust H for maximum RPM (consult tachometer).

CAUTION! Improper adjustment can cause engine damage or unsafe operation.

Storage Procedures

Long-term storage (over 30 days) requires proper preparation.

  1. Drain fuel tank and run engine until it stops.
  2. Remove spark plug, add 1 teaspoon of oil through spark plug hole.
  3. Pull starter cord slowly to distribute oil, reinstall spark plug.
  4. Clean entire saw, apply light oil to bar and chain.
  5. Store in dry place, covered to prevent dust accumulation.

Tip: Use fuel stabilizer if storing with fuel for short periods.

Warranty Information

Craftsman 18 42cc Chainsaw comes with a 2-year limited warranty covering defects in materials and workmanship. Warranty does not cover normal wear, misuse, or improper maintenance. Keep original receipt as proof of purchase. For warranty service, contact Craftsman Customer Service at 1-888-331-4569 or visit www.craftsman.com.

Troubleshooting

SymptomPossible CauseCorrective Action
Engine won't startOld fuel, clogged filter, no sparkUse fresh fuel mix; clean/replace air filter; check spark plug gap (.025")
Engine runs poorlyDirty carburetor, fuel line issuesClean carburetor; inspect fuel lines for cracks; adjust carburetor
Chain doesn't turnClutch worn, drive sprocket damagedInspect clutch shoes; replace drive sprocket if worn
Excessive vibrationLoose components, unbalanced chainTighten all fasteners; balance chain by sharpening evenly
Chain throws oilOver-oiling, wrong oil viscosityAdjust oiler screw; use proper bar & chain oil
Chain comes off barLoose chain, worn bar, damaged drive linksProperly tension chain; replace bar if worn; inspect chain for damage

Service: For technical assistance, call 1-888-331-4569 or visit www.craftsman.com/parts

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