83 mercury 150 help. No full throttle.

[Norcalcj]

Just pickup a bass boat with an 83 merc 150 2stroke . when i try to go full throttle it boggs out . idle is great and starts great , low rpm is just ok. ive changed the plugs , checked all sprak , new gas , revuilt the fuel pump and waiting on the gaskets for the carbs . i took one carb apart and noticed a break in the thin piece of gasket in between the barrels . could the be causeing this lack of power problem ? Not sure how to add pictures , im doing this from my phone .

 

[Norcalcj]

Trying to post a pic .