250 ox66 power loss

i think my motor is in limp mode. im getting a temp light flashig on my gauge and my motor wont run over 3200 rpm. wen it hits that it jumps back down to like 2000 or so. it idles fine and sounds strong.i cleaned the o2, and check the lp pumps. what should i do next?

also vst pump is clean ,new plugs installed. im this poppit valve??
help!!

[boats.net]

If warnings system has been activated then buzzer should sound, have you checked to see if buzzer is working ok? If engine is overheating then probably need to replace water pump.