Small Engines (Lawn Mowers, etc.): Toro S-140 Model 38100

Question
This unit I have had for over 25 year and every year it started up on the first couple of pulls. For some reason this year it is very hard to start. I will take 20 or 30 hard pulls to start even when I ran it and shut it off for just a few minutes. I have new spark plug and fresh fuel with proper mixture.

Answer
S140 14" 1979-1981
Tecumseh engine: model AH520
Engine Type number:  Depends on serial number of blower unit
Mix ratio: 32:1
Max RPM:  4100-4500
Spark Plug:  Champion RJ18YC
Spark Plug gap:  0.035

Snowblower service manual URL:

http://www.toro.com/en-gb/parts/Pages/PartsDetails.aspx?mybeid=2915&serialNumber

Engine service manual URL:

http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/Tecumseh_2-Cycle_


When was the last time the carburetor was rebuilt?  According the parts diagram, you have a Tecumseh engine with a diaphragm type carburetor.  The metering diaphragm gets stiff and brittle over time and will cause the carburetor not to function.

I'd start by removing, dis-assembling and inspecting the carburetor.  Most likely it will need a carb rebuild kit, Tecumseh part number 631893.

Your engine may have points and a condenser...you will have to verify the engine type or inspect to see if you engine has points.

Search You Tube for "Tecumseh diaphragm Toro S140 rebuild" and you will find several videos covering rebuilding the carburetor.

Eric