Craftsman Carburetor Problems | Repair Guide

Craftsman mowers use Briggs & Stratton engines almost exclusively. When your Craftsman won’t start or runs rough, the carburetor is usually the culprit. This guide covers carb diagnosis and repair for all Craftsman mower models.

Table of Contents

• Carburetor by Model
• Common Symptoms
• Cleaning Procedure
• Replacement Parts
• Model-Specific Issues
• Troubleshooting Tips

Carburetor by Model

Craftsman uses different Briggs engines across their lineup. The carburetor depends on the engine, not the mower model name.

[NEED REAL IMAGE: Craftsman mower engine identification label]

Push Mower Carburetors

Mower Model	Engine	Carburetor	Briggs Part
M100	Briggs 140cc	Plastic bowl	799866
M110	Briggs 140cc	Plastic bowl	799866
M140	Briggs 140cc	Plastic bowl	799866
M210	Briggs 163cc	Plastic bowl	799866
M220	Briggs 150cc	Plastic bowl	799866
M230	Briggs 163cc	Metal bowl	799871
M250	Briggs 163cc	Metal bowl	799871
M270	Briggs 190cc	Metal bowl	799871

Riding Mower Carburetors

Mower Model	Engine	Carburetor	Briggs Part
T100	Briggs 11.5HP	Nikki	591736
T110	Briggs 17.5HP	Nikki	591736
T130	Briggs 18.5HP	Nikki	591736
T210	Briggs 18HP	Nikki	591736
T240	Briggs 19HP	Nikki	591736
LT1000	Briggs 17.5HP	Nikki	591736
LT2000	Briggs 20HP	Nikki twin	791858

Older Sears Craftsman Models

Vintage Craftsman mowers (sold at Sears before 2017) use similar carburetors:

Engine Series	Carburetor Style	Typical Part
450-500	Plastic body	799866
550-625	Plastic body	799866
675-725	Metal bowl	799871
850-875	Metal bowl	799871
Platinum 7.25	Metal bowl	799871
Gold 6.75	Plastic bowl	799866

Common Symptoms

Won’t Start

The most common complaint. Carburetor issues cause 80% of no-start problems on Craftsman mowers.

What happens:

• Engine cranks but won’t fire
• Primer bulb pushes air but nothing changes
• Starts with starting fluid then dies

Likely causes:

• Gummed jets from old fuel
• Stuck float or needle valve
• Clogged main jet
• Bad primer bulb

[NEED REAL IMAGE: Clogged Craftsman carburetor jet]

Surging or Hunting

Engine speed rises and falls repeatedly, even at idle.

What happens:

• RPM goes up and down on its own
• Worse under load
• May settle after warming up

Likely causes:

• Partially blocked jet
• Air leak at intake gasket
• Governor linkage binding
• Dirty air filter

Hard Starting

Engine requires excessive cranking or special procedures to start.

What happens:

• Only starts with full choke
• Needs starting fluid
• Starts cold but not when warm (or vice versa)

Likely causes:

• Float level incorrect
• Carburetor gaskets leaking
• Weak primer system
• Fuel delivery issue

Dies Under Load

Starts and idles fine but stalls when mowing.

What happens:

• Bogs down in tall grass
• Dies when blades engaged
• Restarts easily

Likely causes:

• High-speed jet clogged
• Fuel delivery can’t keep up
• Governor not responding
• Air filter plugged

Black Smoke

Engine runs but produces excessive black exhaust.

What happens:

• Sooty exhaust
• Fouls spark plugs
• Poor fuel economy

Likely causes:

• Float stuck open (flooding)
• Choke stuck closed
• Wrong jet (aftermarket carb)

Cleaning Procedure

Most Craftsman carburetor problems are fixed by thorough cleaning.

Tools Needed

• 10mm socket and wrench
• 8mm socket
• Flathead screwdriver
• Carburetor cleaner spray
• Compressed air
• Small wire or needle
• Shop towels
• Safety glasses

Step-by-Step

1. Prep and Safety

Disconnect spark plug wire. Work outside or in a well-ventilated space. Keep away from flames.

2. Remove Air Filter Assembly

Take off the air filter cover and element. Note how components fit together.

3. Shut Off Fuel

Close fuel valve if equipped. Otherwise pinch the fuel line with locking pliers.

4. Disconnect Linkage

Unhook throttle linkage and choke linkage from the carburetor. Take photos before disconnecting.

5. Remove Carburetor

Remove the two mounting bolts (usually 10mm). Pull the carburetor off the intake. Keep track of gaskets.

6. Remove Float Bowl

One bolt holds the float bowl on. Remove it and the bowl. Some fuel will drain out.

7. Remove Float and Needle

Pull the float pin and remove the float. The needle valve comes out with it or separately.

8. Identify and Clean Jets

The main jet is in the center post. Some carbs have it pressed in, others threaded.

• Spray carb cleaner through every hole
• Use thin wire to clear stubborn blockages
• Pay attention to the tiny holes in the emulsion tube
• Clean the main jet thoroughly

9. Inspect Parts

Look for:

• Cracked or waterlogged float
• Worn needle tip
• Damaged gaskets
• Corroded surfaces

10. Reassemble

• Install new gaskets if available
• Set float level (should be parallel with bowl edge when inverted)
• Reinstall carburetor
• Reconnect all linkage

Replacement Parts

OEM Briggs Carburetors

Part Number	Engine Type	Price Range
799866	450-625 series (plastic)	$25-40
799871	675-875 series (metal)	$35-50
591736	17-19.5HP Intek	$45-70
791858	Intek V-Twin	$55-80
594287	725-850 push	$30-45

Rebuild Kits

If the carburetor body is good, a rebuild kit saves money:

Kit Part	Fits Carbs	Contents	Price
498260	799866 style	Gaskets, needle, seat	$8-12
694056	799871 style	Gaskets, needle, float	$10-15
792006	Nikki 591736	Gaskets, needle	$12-18

Aftermarket Options

Aftermarket carburetors cost significantly less than OEM.

Brands to consider:

• HIPA - Generally reliable
• AUTOKAY - Decent quality
• Buckbock - Budget option

Aftermarket notes:

• May need jet cleaning out of the box
• Gasket quality varies
• Some require adjustment after install
• Verify part number match before buying

[NEED REAL IMAGE: OEM vs aftermarket Craftsman carburetor]

Model-Specific Issues

M110 and M140 Carburetor Issues

These entry-level push mowers use the smallest Briggs engines.

Won’t prime: The primer bulb system fails frequently.

• Check bulb for cracks
• Verify primer hose connected at carb
• Replace bulb ($5 part)

Fuel leaking from air filter: Float needle not seating properly.

• Remove and inspect needle
• Clean needle seat
• Replace needle if worn

M220 and M230 Carburetor Issues

Mid-range Craftsman mowers with self-propel.

Surging at idle: Common on these models.

• Clean idle circuit thoroughly
• Check for intake gasket air leaks
• Verify governor spring tension

Hard starting after sitting: Fuel varnishes quickly in these carbs.

• Drain fuel if storing over 30 days
• Use fuel stabilizer
• Run engine dry before storage

Riding Mower Carburetor Issues

Craftsman riders use larger Nikki carburetors on Intek engines.

Hot start problems: Engine hard to restart when warm.

• Fuel percolation from engine heat
• Install heat shield between carb and engine
• Check exhaust manifold for leaks

Idle solenoid failure: These carbs have an electric fuel shutoff solenoid.

• Solenoid should click when key is on
• No click = bad solenoid or low voltage
• Replace solenoid or check battery

[NEED REAL IMAGE: Craftsman riding mower Nikki carburetor]

Fuel pump issues: Riding mowers have the tank below the engine so a fuel pump is needed.

• Check pump pulse line for cracks
• Test pump output
• Replace pump if not delivering fuel

Snowblower Carburetor Issues

Craftsman snowblowers share engines with mowers but face cold-weather challenges.

Won’t start after summer storage: Fuel left in carb turns to varnish.

• Complete carburetor disassembly needed
• Clean all passages thoroughly
• Use fuel stabilizer before storing

Dies when auger engaged: Carb can’t deliver enough fuel under load.

• Clean high-speed circuit
• Check fuel delivery system
• Verify governor function

Troubleshooting Tips

Fuel Delivery Test

Before blaming the carb, verify fuel is reaching it:

1. Disconnect fuel line at carburetor
2. Aim into container
3. Turn on fuel or crank engine briefly
4. Fuel should flow steadily

No flow = tank issue, line blockage or fuel shutoff closed.

Spark Test

Rule out ignition problems:

1. Remove spark plug
2. Ground plug against engine
3. Pull starter cord
4. Look for blue spark

No spark = ignition issue, not carburetor.

Compression Test

Low compression mimics carburetor symptoms:

1. Remove spark plug
2. Install compression tester
3. Pull cord several times
4. Should read 60-90 PSI

Below 60 PSI = engine issue, not carb.

Intake Leak Test

Air leaks cause surging:

1. Start engine (if possible)
2. Spray carb cleaner around intake gasket
3. RPM change indicates leak
4. Replace gasket if leaking

Related Guides

• Briggs & Stratton 799866 Carburetor
• Briggs & Stratton 799871 Carburetor
• How to Clean a Carburetor
• Craftsman M220 Problems
• Lawn Mower Won’t Start

Summary

Craftsman carburetors are Briggs & Stratton carburetors with Craftsman branding. The same cleaning and repair procedures apply. Most problems stem from old fuel sitting too long. Clean the carb, use fresh gas and add stabilizer when storing. Do that and most carburetor headaches go away.

If cleaning doesn’t work, replacement carbs are affordable. A $25 aftermarket carb often makes more sense than spending hours on a stubborn old one.