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Dieseljunky2, Mechanic
Category: Small Engine
Satisfied Customers: 3946
Experience:  20+ years in the mechanic industry
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I have a B&S engine on my lawnmower Model(NNN) NNN-NNNN21 and

Resolved Question:

I have a B&S engine on my lawnmower Model(NNN) NNN-NNNN21 and has given me excellent service for a number of years. It has developed a fault - when you start the engine from cold it starts then splutters to a stop. I suspect the carburetor is at fault. Can you tell me what I should look out for. Thanks
Submitted: 6 years ago.
Category: Small Engine
Expert:  Dieseljunky2 replied 6 years ago.

Dieseljunky2 :

Hello, Does it backfire or pop when it is trying to run? Also is there any smoke from the exhaust while this is going on?Thanks


No it just dies !

Dieseljunky2 :

Ok, there is a main jet that is part of the bolt that holds the carb bowl on. In the picture, item 955 is the bolt/jet for the fuel. If you remove the bolt, and the bowl, you can clean them without removing the carb from the engine. Be cafreful as the seal (137) on the bowl to carb sometimes is tricky to reinstall and make sure the needle valve (134) does not fall out while the bowl is off. You can clean the jet holes in the bolt with a small piece of wire and some carb cleaner. Also clean out the bowl of the carb while it is off. Let me know how it goes after this is done. There is one other possibility, that the seal where the carb attaches to the intake tube has failed. The carb jet being clogged is far more common though. If it still doesn't run, then let me know and I can get you pictures of the intake tube and seals. Thanks

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