02 225 4 stroke chugging at low revs

[march222]

Ok, Novice here,
before I go fo for a beating at the dealership, can anyone give me some color on my problem.
When motor is engaged at low speed, engine chugs and shakes a little at higher revs and up onto plane no problem it flys.
500 hrs on engine. Regular maint.
Should I clean injectors?
I just put some seafoam in.

Any Ideas welcome.

[boats.net]

If it runs good at wide open then the injectors are probably ok, it needs to tested to find idle problem.