7hp Craftsman/Briggs mowing w/ new carb stalls when airfilter put on it.

paulinboise

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  • / 7hp Craftsman/Briggs mowing w/ new carb stalls when airfilter put on it.
I have a 7hp craftsman mower and just ordered a new carb, installed it, cranked up first time...fantastic. Until I put the air filter back on. It runs perfectly until I put the air filter on. It runs fine with the filter box/housing on but as soon as you put the filter on top the housing the engine dies immediately. The filter is nearly new, very clean, the filter housing and gasket are on correctly. Help engine model number is 128602-0259-e1

Here is a 15 sec video of what is happening

https://youtu.be/i6lwf72wHb0
 

lugnut1

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  • / 7hp Craftsman/Briggs mowing w/ new carb stalls when airfilter put on it.
filter isn't wet by chance?
either filter is being to restrictive for some reason or engine not creating enough draw to pull fuel from carb with air filter on.

things to check
check for intake gasket leak or intake being restricted by something (debris of some sort)

engine:
intake valve not opening far enough (creating low draw)
compression low (creating low draw)
check to make sure head is tight also
 
Last edited:

paulinboise

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  • / 7hp Craftsman/Briggs mowing w/ new carb stalls when airfilter put on it.
filter isn't wet by chance?
either filter is being to restrictive for some reason or engine not creating enough draw to pull fuel from carb with air filter on.

things to check
check for intake gasket leak or intake being restricted by something (debris of some sort)

engine:
intake valve not opening far enough (creating low draw)
compression low (creating low draw)

Thanks a bunch, filter is dry and new, have tried it with and without foam sleeve. I assume the intake filter gasket is the gasket that goes between the black plastic airbox housing that the filter sits on and the carb? If so, it is a new gasket and matches the old one perfectly.

Thanks again.
 

paulinboise

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  • / 7hp Craftsman/Briggs mowing w/ new carb stalls when airfilter put on it.

Ah, so I have the new 51a carb spacer on but there isn't anything else between that and the carb. Basically the spacer sits between the carb and engine, looks as though there is another gasket that cam with the carb (sticker on one side) that sits between the carb and the spacer?
 

paulinboise

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  • / 7hp Craftsman/Briggs mowing w/ new carb stalls when airfilter put on it.
Ah, so I have the new 51a carb spacer on but there isn't anything else between that and the carb. Basically the spacer sits between the carb and engine, looks as though there is another gasket that cam with the carb (sticker on one side) that sits between the carb and the spacer?

Actually based on the old space the #51 intake gasket sticks to the #51a carb spacer, between it and the engine intake. I did just install the gasket and while it runs a little bit it is still having an issue. Happy to video it but basically the same as earlier, just runs barely instead of complete stall.
 

paulinboise

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  • / 7hp Craftsman/Briggs mowing w/ new carb stalls when airfilter put on it.
Thanks again. I did install the new gasket on the backside of the spacer between the spacer and engine. Still have the issue.

I just wanted to follow up, although it didn't look like it, the filter was oiled and was the problem. New $10 airfilter and it worked perfectly.

Thanks again for your help!
 
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