With the engine off, make sure the secondaries open fully.

Readjust the air door, make it harder to open.

Does it have a choke and is it fully opening?

Are you running out of fuel?

When the fuel pump on my 273 started to go the first symptoms were similar to what you describe.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.