sluggish engine

[1stpriority]

I have twin 1994 yamaha 250 txrs outboards on my boat. The right motor runs strong up to 5700 rpm and the left is having problems at wot it will go to 5400 rpm. They used to both hit 5700. When I gun just one motor at a time the right runs strong to 4300 by itself and the left feels sluggish and hits 3700. I ran all new fuel lines , new fuel fiters and rebuilt the carbs,new fuel pumps, new tstats, new sparkplugs. I have the diagnostic light and hooked it up with no codes tripping. It has good response off idle but just doesnt have the power. like the right one. good compression 115 to 120 all cylinders. The next step I am guessing is the timing not advancing for some reason. Any help would be appreciated. I have the manual for the motor and it doesnt state if I can adjust the timing.

[boats.net]

Need to check throttle synchronization and timing. Check props for damage.

[1stpriority]

I resynched the carbs , I know how to check the timing I believe its at idle 6atdc and full open 18btdc, but can it be adjusted, there is nothing in the yamaha manual thats says the timing can be adjusted