Excessive fuel consumption and backfires

Gta_g20

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So I picked up a used Scott’s mower with a tecumseh 6.5hp. When I first got it running. The air filter was soaked wiith oil and gas and had to be replaced. After shutting th mower down by releasing the brake it popped and crackled like an old carbureted car that’s was dieseling. It didn’t want to stop running . The mower ran but a horrible smell of gas was present during and after mowing that made my shed a fire hazard it was so strong. I changed the plug. Changed the bowl and gaskets.

I’ve now filled the tank twice in two lawn cutting sessions. It’s run out of gas during half of my yard and it’s not a big yard. This is a xcessive. I’m assuming it’s running rich. How can I control the mixture if even possible on this carb... thanks in advance

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tadawson

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Service manual is here: http://www.barrettsmallengine.com/tecumseh/manuals.html

Looks like a non adjustable carb, but based on your description, the float may be sinking, the seat is damaged or worn, or it was last adjusted incorrectly. Check that first . . . The afterrunning makes me think that it has also been that way for a while and is carboned up in the head, which may require you to pull the head and clean. If all else fails and someone went 'total idiot' on the carb, replacing it is an option, but typically a rebuild of an OEM carb results in a better part than any Chinesium based replacement . . .
 

cpurvis

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It probably isn't an adjustment problem. My guess is the needle valve isn't seating and the float chamber is overfilling.

Does your oil smell like gasoline?

When you get this problem sorted out, use non-ethanol gas only.
 

Gta_g20

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Just filled up and finished the front and back of the lawn.

After I shut off the mower I got one loud pop. Then someone thing was dripping and sizzling couldn’t see if it was oil or gas but smelled like petrol leaking out the exhaust.

Will tear into it tomorrow and check replace the float and needle although they appeared ok

Will also smell the oil, noticed there is an oil leak from the filler tube into the block? Oil seems to be seeping out and bubbling
 

7394

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IS the oil overfull ?

What does the spark plug read like: Black & sooty ?

If you can get 100% gas, use it as Cpurvis recommended & I'd add some Seafoam* to it as well to help clean things up.
 

nbpt100

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Yes, check the spark plug and it sounds like it would be black and sooty (too rich), as suggested. That poping noise is unburned gas burning on the exhaust stroke or burning when it hits the hot muffler.
 

The Chairman

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A carb leak can leak into the crankcase. I change the oil and dump the gas of any used engine I buy. Change all filters too as well as the spark plug. Sometimes a fresh load of gas will dissolve residue that causes the carb to leak.
 
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