4 stroke 40hp Merc cuts out when accelerating

[openorice]

I have a 2001 40hp 4 stroke Merc tiller and it cuts out when I start turning the throttle to go from idle to full throttle. If I twist the throttle back and forth I can keep it from stalling out as it increases to full speed. I've had it worked a number of times and nobody can seem to fix the problem. Any ideas?

[GRA]

I had this problem with a 30 hp. Yamaha 2 stroke. Started out with a motor that would only run with the choke on. I had the carbs off and cleaned them. Motor would then start and run good except for the accelerating part. Went and asked a mechanic and he said I must have missed a hole or passage when I cleaned the carbs. Took carbs off, cleaned again, and must have found the pluuged spot because motor worked just fine after that.

Mechanic said gas today is [PoorWordUsage].

[Big Buck Buster]

The tech is right about the gas. Today's gas is suppose to be used within 60 days if stabilizer is not added.