1973 Mercury 115 2 stroke engine questions

[jimmbo]

A 73 115, has, I believe 2 Fuel Pumps in Series, each with 2 chambers. Not complicated and easy to rebuild.
By the Mid 70s the Fuel System consisted of only One Pump, completely redesigned, and for a while was mounted on the Cowl Pan on the Starboard Side, it was later relocated to the Port Crankcase Cover.

The inline 6s got the newer Power Trim System in 1984, Engines from 1966 through 1983 used the Older System that had the Pump and Reservoir in the Boat and Hydraulic Lines going to the Rams outside the Transom Bracket. This design used SAE 20 as the Fluid
The 1984 system was contained completely between the Transom Brackets, and used ATF.

 

[BulletGenius]

A 73 115, has, I believe 2 Fuel Pumps in Series, each with 2 chambers. Not complicated and easy to rebuild.
By the Mid 70s the Fuel System consisted of only One Pump, completely redesigned, and for a while was mounted on the Cowl Pan on the Starboard Side, it was later relocated to the Port Crankcase Cover.

The inline 6s got the newer Power Trim System in 1984, Engines from 1966 through 1983 used the Older System that had the Pump and Reservoir in the Boat and Hydraulic Lines going to the Rams outside the Transom Bracket. This design used SAE 20 as the Fluid
The 1984 system was contained completely between the Transom Brackets, and used ATF.

Okay so I need to drain and use SAE20, got it.
I have taken the fuel pump apart and not noticed anything amiss (to my unlearned eyes). Should the fuel pump be rebuilt to fix this then? or carb issues?
Thanks

 

[Chris1956]

Yes, rebuild the fuel pump. Make sure there is no air leaks into the fuel line, and no restrictions like dirty fuel filters.