Briggs 135202 5hp runs very rough and burns too much gas

ba_50

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  • / Briggs 135202 5hp runs very rough and burns too much gas
It burns a lot of gas and a little black smoke. I cleaned the fixed jet, changed the plug, and checked the fuel pump. there isn't any blow by at the intake manifold gasket. We did shorten one valve stem since it wouldn't close all the way. Aside from taking the carb off and soaking it in carb cleaner, not sure what to do. The air cleaner is good too. Thanks.
 

bertsmobile1

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  • / Briggs 135202 5hp runs very rough and burns too much gas
:welcome:

Black smoke has 2 causes.
1) too much fuel
2) too late spark.

If while cleaning the fixed jet you enlarged it then it is going t run rich
If the float is allowing the fuel to get too high in th bowl it will run rich


If the timing key in the fywheel is broken and the flywheel is behind where it should be it will blow black smoke.
 

ba_50

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  • / Briggs 135202 5hp runs very rough and burns too much gas
:welcome:

Black smoke has 2 causes.
1) too much fuel
2) too late spark.

If while cleaning the fixed jet you enlarged it then it is going t run rich
If the float is allowing the fuel to get too high in th bowl it will run rich


If the timing key in the fywheel is broken and the flywheel is behind where it should be it will blow black smoke.

Can't be the fuel jet unless through fuel flow which I doubt, so I'll check the key next. Bob
 

ba_50

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  • / Briggs 135202 5hp runs very rough and burns too much gas
The flywheel key was ok, and the motor was running rough before I cleaned the fuel nozzle so I don't know what it could be.
 

bertsmobile1

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  • / Briggs 135202 5hp runs very rough and burns too much gas
My bad, was thinking of wrong mower.
You have the carb on the tank so bowl can not get overfull and cause the engine to flood.
However it does have a choke so if the choke is not partially closing , the carb is clean then get a full rebuild kit with new needles
 

ba_50

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  • / Briggs 135202 5hp runs very rough and burns too much gas
It has a cable operated choke and I checked to make sure it was opening completely and even tried varying it's position while running. There aren't any needles that I know of, just a nozzle.
 

ba_50

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  • / Briggs 135202 5hp runs very rough and burns too much gas
This morning I took the cyl head off and cleaned off a lot of carbon. I put the carburetor in the cleaner since I had it off. The gas tank had dirt in the bowl so it got a cleaning. If I can find the valve clearance measurements again, I double check them. I checked 3 parts places diagrams and couldn't find a carb like mine which only has a fixed jet.
 

BlazNT

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  • / Briggs 135202 5hp runs very rough and burns too much gas
498298 is carb part number.
I found them all over the web. Around $70.00
 

ba_50

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  • / Briggs 135202 5hp runs very rough and burns too much gas
What I meant was I couldn't find one with a jet like mine. Not sure if the carb is the problem or not. I'm wondering if a new Predator motor from Harbor Freight would be the way to go.
 

ba_50

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  • / Briggs 135202 5hp runs very rough and burns too much gas
I believe the problem was the 2 air filters. Even with the sponge only it, wouldn't run right. With both off, it runs normally. The lawn tractors run forever with paper filters but not the tiller.
 
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