725ex won't start

APMech

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So I put my Troy-Bilt push mower with a Briggs and Stratton 725ex up for sale and before someone came to look at it I went to fire it up for the first time after winter. I've never had a problem with it but now it's not starting. The spark plug was pretty dirty so I went ahead and replaced it but nothing. Pulled the plug back out and it's dry as a bone. So I pulled the carb off. The bowl fills up, the float isn't sticking, the inlet tube is clear and the emulsion tube is clear. There's no reason it shouldn't be getting fuel. Any ideas?
 

primerbulb120

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I'm going to guess it's getting fuel, but the fuel isn't fresh. Drain the gas tank, flush it with fresh gas. Clean all the old gas out of the carburetor. Then try to start it on new, fresh fuel. Those engines are VERY picky when it comes to fuel.
 

APMech

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Well I drained the tank and the carburetor and replaced with fresh fuel and still nothing. Sprayed it with starter fluid right in the carb and it fired right up. I found a cheap replacement carb on eBay for like $15 so that should do the trick. Weird that everything in the carb seems fine and clear but it's still not working.
 

eyerobot

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I picked up one of these mowers cheap the other day. Pulled the carb for cleaning, And noticed that it was missing a small 1/4 in section of the intake gasket. Which was causing it to suck air instead of fuel while starting. I cleaned the carb, Even though it was literally unused, Other than the few times they started it with carb cleaner. Made a new gasket for the intake, And it fires on the first pull every time now. I found no residue from there ever being gasket material on that missing spot. So this clearly came from the factory in this condition.
 

cpurvis

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Well I drained the tank and the carburetor and replaced with fresh fuel and still nothing. Sprayed it with starter fluid right in the carb and it fired right up. I found a cheap replacement carb on eBay for like $15 so that should do the trick. Weird that everything in the carb seems fine and clear but it's still not working.
Did you try a few restarts after you got it running? Sometimes all they need is a "jump" start of fuel in the carb throat and then they're OK. Hang on to your old carburetor. I'd buy a kit for it before buying a Chinese carburetor.
 
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