Runs good for 15-20 minutes, engine then starts trying to die! Choking will keep it running, but roughly, then runs good, then bad! After letting engine cool down, it will run good again! This happens over and over again! Always runs good for first 15-20 minutes!
The first thoughts are a vacuum lock in the fuel tank cause the vent is blocked ( loosen the cap ) or debris is plugging the fuel tank outlet.
Fuel supply can not keep up with fuel demand and by 20 minutes there is no longer enough fuel to run.
Quick & dirty test is to toss a small amount < teaspoon of fuel down the carb the instant the engine stops.
If it starts & runs out then that confirms a low fuel situation.
I was having problems with momentary loss of power on my 148 and returned it to dealer and he did a recall on the vapor system he said that cured my problems, and that has been a year ago with no repeat of problem. Call dealer to see if there is a recall.
