Yamaha 150 slow idle/forward issue?

[Bill Mains]

When setting throttle into slow forward indent, runs very smooth..then gets a little rough...smooth again...etc. Is this normal? Asked mechanic at dealership, "I'm not sure" Any suggestions on what he should check?

 

[sunnyside360]

I had a Yamaha F150 and never had any issues --- ran smooth and quiet, especially at slower speeds.   You may have a little water in the fuel.  If it is a newer motor the dealer should figure it out/fix under warranty.

 

[Chris Z]

Should be smooth as silk and very quiet. I have 9 hours on my 150 and it hasn't misbehaved a bit, I'd see your dealer if this keeps happening.