Having alarm problem's 0n 150txru

I'm new at this and desperate to solve a problem on my port side 1996 saltwater series 150txru, Problem: running at any rpms in the bay, in flat calm water engine's run great,
But at any rpm's getting bounced around or come off a wave or on a drift the alarm goes off and tech starts to fludder just on port engine.
If I'm running at 4000 rpms No drop in rpms (alarm still on)
Plenty of water coming out the back.
Plenty of oil in tank's
No engine lights go on,
Temp is Good

[jb123]

which gauges do you use ??

do they show if oil or overheat ??

when it is buzzing, stop to idle, at each cylinder bank top is the thermosensors, unplug pink and black, see if buzzer stops....this would indicate a heat issue.

Yamaha tachometer Number 6Y5-2818R-31 Speed unit fuel sender selection ,digital
temp and oil on bottom ,engine trim angle , speed rpm
Plug ends colors: green,yellow, black, blue wires
Male square harness two wire green ,and green / white line
Female square harness 4 wire pink,black, orange, grey

[jb123]

swap both harnesses at keyswitch so the left switch controls right motor, sounds like you have some electrical issue at keyswitch if you have no gauge lights on and no rpm reduction.

Also check all harness connections, at motor end and front.

went down to boat today to check out the harness on key switch there are 3 loose wires and two sets of quick connect on each key do I have to switch the loose wire's and both quick connects.