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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 29867
Experience:  Service manager and technician for all brands of engines with 40 + years of experience.
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Mtd B12 starts first time when cold without any choke but cuts

Customer Question

Mtd B12 starts first time when cold without any choke but cuts out when been running for about 15 mins. May restart with with full choke but will quiickly cut out and will not restart until cold. I have drained all the fuel including carb and fuel filter and refilled with fresh fuel. I have cleaned the carb renewed the fuel filter and new spark plug. The persists.
Your advice would be greatly appreciated.

Bernard Cole
Submitted: 3 years ago.
Category: Small Engine
Expert:  Curtis B. replied 3 years ago.
Is this the Briggs single cylinder, flat head engine? What is model number of the engine? How old is the unit? Have you already cleaned the carburetor? When it quits and does not restart, do you have spark at the spark plug? Have spare spark plug, when it will not start, pull spark plug wire, attach the spare plug, and with the plug grounded, see if you have spark. If no spark, your coil is bad
Customer: replied 3 years ago.

The ,engine is an 11.5 Tecumseh Enduro XL/C Overhead valve, the model no is 13A1458B600 and the other serial no on the label is AJ292L10012. I am not certain of the age of the unit but I believe it is about 10 years old but has had very little use so appears much newer. I have cleaned the carb.




Expert:  Curtis B. replied 3 years ago.
Do the spark test and see if it is loosing spark. Could be a coil getting hot and cutting out.
Customer: replied 3 years ago.

Have carried out the spark test as you suggested and the spark appears strong.

Expert:  Curtis B. replied 3 years ago.
So you do not loose spark when hot! Seems odd it would be a fuel problem that engine would have to cool before restarting. Have you checked the fuel supply to the carburetor? Maybe there is debris floating the tank , that clears itself when sitting.??
Customer: replied 3 years ago.

Previously I drained the fuel tank via the pipe to the fuel filter put in a new fuel filter drained and cleaned the carb and refilled the tank with fresh fuel. I have checked again today and there is no debris in the tank.

Expert:  Curtis B. replied 3 years ago.
OK< so spark is strong when engine quits and has to cool? Is fuel line routed where it could heat up and vapor lock?
Customer: replied 3 years ago.

The route of the fuel line seems ok and would not appear to be too close to any surface that gets hot.

Expert:  Curtis B. replied 3 years ago.
I personally think you have a bad coil. It has to be loosing spark or gas, and from your tests, it has both!