Small Engines (Lawn Mowers, etc.)/won't run when hot

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Question
My Toro will start but when it gets hot the throtle adjustment becomes irratic. It fluctuates from super high RPM to low and then will stall. It seems that the high RPM is very high and not governed and it will only slow down if I put the choke on.
What do you think this could be? Any help is appreciated.
Paul

Answer
This indicates the carb is dirty inside because the high RPM is caused by a lean condition (carb cannot supply enough fuel) then it dies.  The choke helps because the carb will draw fuel from the low speed circuit in the carb (which isn't blocked).  You need to thoroughly clean the carb, including pushing a piece of tag wire through all of the internal passages.  Hope this helps.

Small Engines (Lawn Mowers, etc.)

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Marc Mielhausen

Expertise

I work on equipment in my spare time for myself, family and friends. I have experience in troubleshooting and fixing lawnmowers, string trimmers, chain saws, tillers, snowmobiles, inboard and outboard motors. As I am not currently employed in this industry, I can be of assistance more in non-brand-specific diagnostic questions. Try me.

Experience

15 years experience (6 professionally & 9 personally) Also have related experience in automotive manufacturing, machining, precision measurement, gauge and fixture design. As long as I can remember I have been troubleshooting and repairing mechanical devices of all types.

Education/Credentials
Ontario Certificate of Qualification for Marine and Small Powered Equipment Technician (1993)
Mechanical Engineering Technician - Materials & Quality (1997)

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