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Carburetor Problem? Briggs and Stratton Lawn Mower


BigRedDog's Avatar
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06-27-10, 06:13 PM   #1  
Carburetor Problem? Briggs and Stratton Lawn Mower

After putting gasoline in the air intake side of the carburetor, my lawn mower starts but it only runs a couple seconds. There is gasoline in the carburetor bowl, but the primer bulb does not squirt fuel into the carburetor. I have cleaned the carburetor by putting it in a carburetor cleaner bath for 15 mins and I have installed a carb kit. More info and guesses below. What should I try next?

The Briggs and Stratton engine is Model 128802, Type 1519-23, Code 95033157. I think it is a 498254 Primer System Carburetor and isn't pictured in the parts manual exactly. There are no adjustable mixture screws.

During cleaning three plugged holes were opened up in the Main Jet (the hex bolt that holds on the bowl). I also removed and replaced the Welch plug (and sealed it with nail polisher) and am certain that those passageways were open.

The part that the Main Jet screws into has two holes. One, which is a tube into the carburetor venturi area is open. However, I'm not sure whether the other hole is open because I can't figure out where it goes and when I try to blow air into it I can't tell that the air comes out anywhere. I pushed a plastic bristle from a broom into it. It seems plugged or maybe it tees into something and can't make the turn.

I want to work on this some more and either fix it or break it so no one else can embarrass me. New carburetor is about $40.

 
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06-27-10, 07:30 PM   #2  
Posted By: BigRedDog After putting gasoline in the air intake side of the carburetor, my lawn mower starts but it only runs a couple seconds. There is gasoline in the carburetor bowl, but the primer bulb does not squirt fuel into the carburetor. I have cleaned the carburetor by putting it in a carburetor cleaner bath for 15 mins and I have installed a carb kit. More info and guesses below. What should I try next?

The Briggs and Stratton engine is Model 128802, Type 1519-23, Code 95033157. I think it is a 498254 Primer System Carburetor and isn't pictured in the parts manual exactly. There are no adjustable mixture screws.

During cleaning three plugged holes were opened up in the Main Jet (the hex bolt that holds on the bowl). I also removed and replaced the Welch plug (and sealed it with nail polisher) and am certain that those passageways were open.

The part that the Main Jet screws into has two holes. One, which is a tube into the carburetor venturi area is open. However, I'm not sure whether the other hole is open because I can't figure out where it goes and when I try to blow air into it I can't tell that the air comes out anywhere. I pushed a plastic bristle from a broom into it. It seems plugged or maybe it tees into something and can't make the turn.

I want to work on this some more and either fix it or break it so no one else can embarrass me. New carburetor is about $40.
Did you clean the bowl nut(main jet) it has some holes that if stopped up would create your problem. Gave a good one. Geo

 
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06-27-10, 07:41 PM   #3  
Posted By: geogrubb Did you clean the bowl nut(main jet) it has some holes that if stopped up would create your problem. Gave a good one. Geo
Yes, I did (third paragraph). I checked it just now too.
My post is too long to take in. Sorry.

 
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06-28-10, 04:10 PM   #4  
I had same problem with carb apart 3 times, well the 3rd time I got it. mine would only run if choked. the area on the main jet/ bowl bolt where the two holes are needs to be VERY clean. The extra hole where the main nozzle is I do not know either what it is, on mine it served no purpose whatsoever.
The only thing I did on the carb the 3rd time around was to polish the bolt in the area of those two holes all the way around. Then it ran like it should.

 
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06-28-10, 07:35 PM   #5  
You could have 1 carb feeding both cylinders or 2 carbs that have to be synchronized to operate both carbs together. One recommendation is don't reject if all you need is to clean them out. I consider this a springtime ritual if the bike hasn't been ridden over the winter. Don't let gas sit in the carbs over Winter.

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07-03-10, 03:37 PM   #6  
Thanks 5DollarAlien

The lawnmower is running well now. 5DollarAlien, you were correct. I cleared the main jet once, but after you encouraged me to recheck, I found it was plugged again. I took the tank off and cleaned it too. Thanks for all the help.

 
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07-04-10, 03:49 AM   #7  
yr welcome, sometimes things workout
glad you got it going
wish we had some rain here, would like to mow once in awhile

 
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