Briggs motor only runs on choke

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Lawnmower will only run on choke, took the brand new carb and cleaned it, not a thing wrong with it. Getting plenty if fuel to the carb. Adjusted valves, check compression, checked for spark, all good. Anything else I can check that I'm missing. Thanx
 
Originally Posted by tundraotto
Too small a jet in the carb or dirt in it.....just buy a new cheap replacement carb.

Why not clean the jet instead?
 
Went through the carb completely with carb cleaner, all jets clean.
 
Not sure what vintage it is but on the side of the carb there is a small plate held on by 3 or 4 screws there is a diaphragm and a spring under that plate. Your diaphragm is shot. Replace it.
The diaphragm is your fuel pump.
 
Last edited:
Originally Posted by tig1
Originally Posted by tundraotto
Too small a jet in the carb or dirt in it.....just buy a new cheap replacement carb.

Why not clean the jet instead?


because fully cleaning the carb - esp diaphgram is a pain, and often not successful - and a new carb is about the same price as a carb kit.

Depends on how sentimental you are about the carb that doesn't work I guess.
 
Ok I will have to check that, dont remember seeing anything like that but I could be wrong.
 
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I was wrong the motor is actually considered a MTD motor. Carb has nothing like that on the side of it, tell u the truth I dont even know where the diaphragm is on this carb.
 
Get a drill kit like this one and find the bit that fits. Then run the next bigger one through your main jet. If you notice an improvement but it's still not great, do it again!

I had to do this to a brand new carb I put on a briggs generator I got at the dump. Sometimes carbs are, well, universal, and don't do well with our lean running E10 gas.
 
The diaphragm carbs are mounted directly on top of the gas tank. If you have a bowl type carb with a separate gas tank, there is no diaphragm.
 
So it's just gravity fed then. So pretty much there has to be something in the carb?
 
You have to run a fine stylet through every jet and venturi. Just disassembling and spraying with cleaner does not always do it.
 
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