60Hp struggles getting there

"Hi,This is my first post here

"Hi,This is my first post here ..got a problem with the out board..
The motor is a mariner 60 HP..it is a 2 cylinder and on the plate it shows 60E..i don’t know how old it is.Fitted to a 15ft glass hull.here is the problem:
The boat has been sitting for about 2 years and some one has tried to start it at some stage and left the fuel hose attached.its housed at my fathers place.so I didn’t know..
I took it out yesterday for the first time and it fired up fine first go with new fuel in tanks.i went to accelerate and it started to die on me so I backed off and couldn’t get onto the plane.i ran it for about 20 minutes then my passenger started pumping more fuel in with the primer on the hose and the boat started picking up speed and got to 2/3 rds speed.
Today I had checked the fuel filter and it was clean.made sure the fuel line to filter wasn’t clogged..any ideas what may be stopping from getting to full power..it struggles getting there and shows a bit of a miss and cough.cheers"

Since it has been sitting so l

Since it has been sitting so long you need to rebuild the carbs and fuel pump. The get gummed up from old gas sitting in them so long.

"As it seemed to have been pic

"As it seemed to have been picking up on power and did run at higher revs with out pumping more fuel, would it be worth running a full tank of fuel through it to see if it comes good.."

"So , the advice given here is

"So , the advice given here is to clean the carburetors and you want to see if it will " fix itself ".Doing that you run the risk of one or both cylinders running lean on fuel and therefor oil as well.Take the advice and clean the carburetors!"

Thank you for the advice and i

Thank you for the advice and i will follow through in getting them cleaned..