Craftsman SB650 Snowblower Problems | Repair Guide

The Craftsman SB650 is a popular two-stage snowblower sold at Lowe’s. Built by MTD, it offers good value for homeowners who need serious snow-clearing capability. When problems develop, this guide helps diagnose and resolve common issues across all Craftsman two-stage snowblower models.

Table of Contents

• Model Overview
• Engine Problems
• Auger System Issues
• Drive System Problems
• Chute Controls
• Maintenance Schedule

Model Overview

Craftsman offers several two-stage snowblower models:

Model	Engine	Width	Features
SB450	208cc	24”	Entry two-stage
SB650	254cc	28”	Mid-range
SB850	306cc	28”	Premium

SB650 specifications:

• Engine: 254cc LCT OHV 4-stroke
• Clearing width: 28”
• Intake height: 21”
• Stages: Two-stage (auger + impeller)
• Speeds: 6 forward, 2 reverse
• Electric start: Yes

[NEED REAL IMAGE: Craftsman SB650 showing controls]

MTD Built

Craftsman snowblowers are manufactured by MTD, the same company that makes Troy-Bilt and Cub Cadet. Parts are often interchangeable between these brands.

Engine Problems

Won’t Start

Most common cause: Old fuel from summer storage.

Troubleshooting sequence:

1. Check fuel - Fresh gas under 30 days old?
2. Fuel valve - Must be ON
3. Choke - Full choke for cold start
4. Throttle - Set to FAST
5. Prime - 2-3 presses of primer bulb

Starting procedure:

1. Turn fuel valve ON
2. Set choke to FULL
3. Move throttle to FAST
4. Press primer 2-3 times
5. Pull cord or press electric start
6. Move choke to RUN after engine warms

If still won’t start:

• Spray starting fluid into carburetor
• If fires briefly = carburetor problem
• If nothing = spark or compression issue

See our snowblower won’t start guide for detailed troubleshooting.

Hard Starting After Summer Storage

Old fuel varnishes carburetors quickly. This is the #1 seasonal problem.

Fix:

1. Drain old fuel from tank
2. Drain carburetor bowl (small screw at bottom)
3. Add fresh fuel
4. Try starting
5. If still won’t start, carburetor cleaning needed

See our how to clean a carburetor guide.

Engine Surges

Engine RPM rises and falls repeatedly.

Causes:

1. Dirty carburetor jets
2. Poor fuel quality
3. Air leak at intake gasket
4. Governor linkage issue

Solutions:

• Replace fuel with fresh
• Clean carburetor thoroughly
• Check intake gasket
• Verify governor moves freely

Engine Lacks Power

Causes:

1. Old or bad fuel
2. Dirty air filter
3. Worn spark plug
4. Carburetor running lean
5. Exhaust blockage

Check order:

1. Replace fuel
2. Clean/replace air filter
3. Install new spark plug
4. Service carburetor

[NEED REAL IMAGE: Craftsman snowblower engine]

Auger System Issues

Auger Won’t Turn

When you engage the auger lever and nothing happens.

Check in order:

1. Shear pins - If broken, auger freewheels on shaft
2. Auger belt - Worn or broken
3. Auger cable - Broken or maladjusted
4. Ice jam - Frozen debris blocking

Shear pin inspection:

1. Look at auger shaft on each side
2. Pins should be intact
3. If auger spins freely on shaft, pins are broken
4. Replace with correct Craftsman shear pins

Broken Shear Pins

Shear pins protect the gearbox by breaking when auger hits something hard.

Important:

• Always use correct OEM shear pins
• Never substitute regular bolts (damages gearbox)
• Keep spare pins with machine
• Check both sides after hitting debris

Shear pin replacement:

1. Align holes in auger and shaft
2. Insert new shear pin
3. Install cotter pin
4. Test operation

Weak Snow Throwing

Snow doesn’t throw as far as expected.

Causes:

1. Engine not at full RPM
2. Auger belt slipping
3. Impeller clearance too large
4. Chute blockage
5. Wet heavy snow

Impeller kit: Consider installing an impeller kit to reduce clearance between impeller and housing. Dramatically improves throwing distance.

Auger Belt Replacement

Belts wear over time and should be inspected annually.

Signs of worn belt:

• Slipping under load
• Squealing noise
• Visible cracks or glazing
• Belt rides high in pulley

Drive System Problems

Won’t Move Forward

Check in order:

1. Drive lever engaged - Must be held
2. Speed selector - Set to a speed
3. Drive belt - Inspect condition
4. Friction disc - May be worn

Friction Disc System

Craftsman uses a friction disc drive system for variable speed.

How it works:

• Rubber disc contacts metal drive plate
• Position determines speed
• Wear reduces grip

Friction disc problems:

• Slipping under load
• Jerky movement
• No drive at all

Adjustment: As disc wears, it needs adjustment. Eventually requires replacement.

Replacement: Replace disc when:

• Rubber is smooth/glazed
• Cracks or chunks missing
• Can’t adjust for proper engagement

Drive Belt

Signs of worn drive belt:

• Slipping when drive engaged
• Slow movement
• Belt squeal

Replacement: Annual inspection recommended. Replace if cracked or worn.

[NEED REAL IMAGE: Craftsman snowblower drive system]

Chute Controls

Chute Won’t Rotate

Manual chute causes:

1. Ice/snow buildup - Most common
2. Crank mechanism frozen
3. Cable broken
4. Gearbox worn

Fixes:

• Clear ice with brush or warm water
• Lubricate mechanism with silicone spray
• Check cable connection
• Replace worn gearbox

Chute Clogs

Prevention:

• Apply silicone spray or non-stick spray
• Don’t force wet heavy snow
• Clear before it packs
• Take smaller passes

Clearing clogs:

1. Stop engine
2. Use clearing tool (never hands!)
3. Clear chute and impeller area
4. Apply non-stick treatment
5. Restart

Deflector Won’t Stay

Causes:

• Friction mechanism worn
• Pivot frozen
• Spring broken

Fix: Adjust or replace friction mechanism.

Maintenance Schedule

Before Each Use

• Check oil level
• Verify fresh fuel
• Inspect shear pins
• Test controls
• Check tire pressure

Every 5 Hours

• Check auger/drive belt tension
• Lubricate chute mechanism
• Clear any ice buildup

Every 25 Hours

• Change engine oil
• Inspect belts for wear
• Lubricate all pivot points
• Check cable adjustments

Annually (Pre-Season)

• Replace spark plug
• Replace fuel filter
• Inspect all belts
• Check friction disc
• Fresh fuel

Storage (End of Season)

Fuel system:

1. Run fuel dry or add stabilizer and run 5 minutes
2. Drain carburetor bowl

Engine:

1. Change oil
2. Remove spark plug, add oil to cylinder
3. Pull cord slowly

General:

1. Clean entire unit
2. Lubricate moving parts
3. Store in dry location
4. Cover to protect

For storage tips, see our small engine storage guide.

Common Parts

Part	Craftsman Number	Price
Shear pin kit	Various	$8-12
Auger belt	Various	$20-30
Drive belt	Various	$20-30
Friction disc	Various	$25-40
Spark plug	Various	$5-8
Skid shoes	Various	$15-25

Related Guides

• Snowblower Won’t Start
• How to Clean a Carburetor
• Small Engine Storage
• Troy-Bilt Squall Problems
• Ariens Deluxe 28 Problems

Summary

The Craftsman SB650 offers good value for homeowners needing a capable two-stage snowblower. Most problems trace back to fuel system issues from summer storage. Always stabilize fuel or run dry before storing. Keep shear pins on hand - they’re designed to break and protect the gearbox. The friction disc drive system needs periodic adjustment and eventual replacement. With proper maintenance, these machines will clear snow reliably for 10-15+ years.