Tecumseh Carburetor Repair | Snowblower Guide
Tecumseh engines powered millions of snowblowers, lawn mowers and other equipment from the 1960s through 2008 when the company closed. These engines are still running everywhere, and their carburetors eventually need attention. This guide covers identification, repair and adjustment of common Tecumseh carburetors.
Table of Contents
- Identifying Your Tecumseh Carburetor
- Common Tecumseh Carburetor Types
- Failure Symptoms
- Rebuild Procedure
- Adjustment Guide
- Finding Replacement Parts
Identifying Your Tecumseh Carburetor
Tecumseh used several carburetor manufacturers and designs over the decades.
Engine Model Location
Find your engine model number on:
- Metal tag on blower housing
- Stamped into the flywheel shroud
- On a label near the recoil starter
Model number format examples:
- HMSK80 (horizontal shaft, medium frame, snow king, 8.0 HP)
- LEV100 (vertical shaft, 10.0 cubic inch)
- OH195 (overhead valve, horizontal shaft, 195cc)
[NEED REAL IMAGE: Tecumseh engine model tag location]
Carburetor Identification
Once you have the engine model, look for the carburetor number stamped on the carb body. Common formats:
- 632xxx (most common)
- 640xxx
- 631xxx
Popular Part Numbers:
| Part Number | Engine Types |
|---|---|
| 632334A | HMSK, LH, OH series |
| 632230 | LEV series |
| 640025 | Snow King |
| 632370A | H50, H60 |
| 631921 | Vector series |
| 640349 | OH195, OHH |
Common Tecumseh Carburetor Types
Fixed-Jet Carburetors
Most common on consumer equipment. No adjustable mixture screws.
Characteristics:
- Plastic primer bulb
- Fixed main jet in emulsion tube
- Bowl-type with float
- Simple, disposable design
Adjustable Carburetors
Found on commercial and older equipment.
Characteristics:
- High and low speed mixture screws
- More tunable
- Better performance when properly adjusted
- Requires periodic adjustment
Diaphragm Carburetors
Used on some string trimmers and small engines.
Characteristics:
- No float bowl
- Rubber diaphragm pumps fuel
- Can run in any position
- Walbro or Zama manufactured
Failure Symptoms
Hard Starting - Classic Tecumseh Problem
These engines are notorious for hard starting, especially in cold weather.
Common causes:
- Gummed pilot circuit (most common)
- Weak primer bulb
- Choke not closing fully
- Ethanol damage to fuel system
Won’t Start After Summer Storage
Snowblower sat all summer with fuel in it. Now it won’t fire.
What happened: Ethanol fuel absorbed water and varnished the carburetor. Very common.
Fix: Full carburetor cleaning or replacement.
Starts But Dies When Throttle Opened
Idles okay but stalls when you try to engage auger or advance throttle.
Causes:
- Main jet clogged
- Fuel filter restricted
- Tank vent blocked
Surging at Idle
Engine speed hunts up and down without throttle input.
Causes:
- Lean mixture from restricted passages
- Air leak at carb gasket
- Governor linkage issue
Runs But Lacks Power
Snowblower moves snow poorly. Engine bogs under load.
Causes:
- Main jet restriction
- Exhaust blockage (check for mouse nest)
- Valve issue (not carb related)
Fuel Leaking From Primer Area
Common Tecumseh problem. Gas drips from near the primer.
Causes:
- Cracked primer bulb
- Failed welch plug under primer
- O-ring seal deterioration
Rebuild Procedure
Tecumseh carburetors are rebuildable with readily available kits.
Rebuild Kit Contents
A typical kit includes:
- Float bowl gasket
- Inlet needle and seat
- Welch plugs (cover fuel passages)
- O-rings and seals
- Sometimes a new float
Cost: $8-15 for most kits
Disassembly Steps
1. Remove carburetor from engine
Document linkage positions with photos. Remove air filter, disconnect fuel line, unbolt carb from intake.
2. Remove bowl and float
Bowl is usually held by one bolt or a bail wire. Remove float hinge pin and lift out float with needle.
[NEED REAL IMAGE: Tecumseh carburetor disassembled showing float, needle, bowl]
3. Remove main jet/emulsion tube
Some are threaded, some press-fit. If pressed, don’t force removal unless replacing.
4. Remove welch plugs
Use a small pick or punch to pop them out. They cover internal passages that need cleaning.
5. Remove mixture screws (if equipped)
Count turns before removing. Write down the numbers.
Cleaning
Soak in carburetor cleaner: All metal parts, 1 hour minimum. Overnight for heavy varnish.
Clear every passage: Use carb cleaner spray and compressed air. Focus on:
- Main jet and emulsion tube holes
- Pilot circuit (tiny holes near throttle plate)
- Primer passages
- Idle transition ports
Clean welch plug cavities: These hide clogged passages.
Reassembly
Install new welch plugs: Tap flat (not concave) with a punch slightly smaller than the plug. Seal with fingernail polish if desired.
Install inlet needle and seat: Clean seat area first. Use new needle.
Set float height: With carb inverted, float should be parallel to body or per spec (typically 0.200” below gasket surface).
Install new bowl gasket: Never reuse.
Set mixture screws to baseline: (If adjustable)
- Main/high speed: 1.5 turns out
- Idle/low speed: 1 turn out
Adjustment Guide
Fixed-Jet Carburetors
Limited adjustment available:
- Idle speed screw - Adjusts throttle stop
- Choke - May need manual adjustment for proper closure
Adjustable Carburetors
High Speed (Main) Mixture:
- Start engine and warm up
- Run at full throttle
- Turn screw clockwise until engine stumbles (lean)
- Turn counterclockwise until engine stumbles (rich)
- Set midway between the two points
Low Speed (Idle) Mixture:
- Set engine to idle
- Turn screw for highest RPM without surging
- Typically 1-1.5 turns out from seated
Idle Speed:
- Adjust throttle stop screw for 1400-1600 RPM idle
- On snowblowers, this may be higher (1800-2200) depending on model
Governor Adjustment
If engine speed is wrong after carb work:
- Loosen governor arm clamp
- Rotate governor shaft clockwise (viewed from above)
- Move throttle to wide open
- Tighten clamp
- Check no-load RPM with tachometer
Typical governed speeds:
- Snowblowers: 3200-3600 RPM
- Mowers: 2800-3200 RPM
Finding Replacement Parts
Tecumseh went out of business in 2008, but parts are still available.
Parts Sources
LawnMowerParts.com - Good selection of Tecumseh parts Jack’s Small Engines - Extensive inventory Amazon - Aftermarket carburetors and kits eBay - NOS (new old stock) and used parts Local small engine shops - May have stock
Aftermarket Options
Complete aftermarket carburetors run $12-25 and work well for most applications. Brands like Lumix and Buckbock offer direct replacements.
Quality considerations:
- Check jet sizes match your engine
- Inspect for casting flash
- Verify linkage hole positions
Cross-Reference Guide
When your exact part number is unavailable:
- Find your engine model number
- Search “Tecumseh [engine model] carburetor”
- Verify specifications match (throat size, linkage type)
- Aftermarket sellers often list compatible models
Specific Engine Guides
HMSK80/HMSK100 (Snow King)
Most common snowblower engines.
Typical carb: 632334A or 640349 Common issues: Primer system failure, frozen choke Notes: Choke linkage must move freely in cold weather
LEV100/LEV115/LEV120
Push mower engines.
Typical carb: 632230 or 640025 Common issues: Main jet clogging, primer cracking Notes: Usually simpler fixed-jet design
OH195/OHH series
Overhead valve engines on premium equipment.
Typical carb: 640349 or similar Common issues: Same as others - fuel deterioration Notes: Better performing engines, worth maintaining
Frequently Asked Questions
My Tecumseh has no spark - is it the carburetor?
No. No spark is an ignition issue (coil, flywheel key, kill switch). Carburetor affects fuel only.
Can I use a universal carburetor on my Tecumseh?
Some universal carbs work. Match throat diameter and linkage style. May require adapter plate.
Why does my snowblower start fine but die when I put it in gear?
Usually not the carb. Check belt tension, shear pins and auger engagement system.
How often should I rebuild the carburetor?
Depends on fuel quality. With stabilized fresh fuel, every 5-7 years. With neglected fuel, maybe every year.
Is it worth rebuilding or should I replace?
Rebuild if: carb is in good physical condition, just gummed up Replace if: corrosion present, throttle shaft worn, multiple failed rebuilds
Tecumseh engines are proven workhorses. Even though the company is gone, these engines will run for decades with basic maintenance. Don’t let a $15 carburetor send an otherwise good engine to the scrapyard.