2001 Merc 125hp only have idle no power

[Bigdub18]

Got a 2001 Mercury 125 2 stroke on my 2001 Starcraft pontoon. The boat starts up fine but when I put throttle to it I don’t have any more power than idle, 800rpm at full throttle is all I have. If you pump the fuel primer while driving I get a couple hundred more rpm. Not sure what’s wrong. Any thoughts??

 

[alldodge]

Is the linkage opening up the carbs?
If carbs are opening, then check compression

 

[tommarvin]

Sounds like shes starved for gas ,if she goes faster if you squeeze the primer bulb.
You should remove the carbs ,watch all the you tube videos on carb cleaning/rebuilding maybe if you trash a gasket.
Then clean your carbs, idle jets work bu the high speed jets are plugged.

 

[schematic]

also check for spark at each plug. You may only be running on a few cylinders