Engine dies out unless primed till warm

[Cincyredsfan513]

I have a Briggs 128602 0151 on a Sarlo mower. It has a carb with primer but no choke. It will start after a couple of primes but will stop unless the primer is pushed to feed more gas. This stops once the engine warms up. I have already taken the carb apart and cleaned it in an ultrasonic cleaner, the needle and seat were also replaced. It is easy to start when cold, just needs help to get it warm, then it’s fine. Any idea of what is going on? Thanks.

 

[Rivets]

Need to check your float level. Probably not level, when you turn the carb upside down you will probably find that the float is higher on the side away from the pin. This will result in a lean mixture, which will work fine when the engine gets warm, but creates problems when the engine is cold.