What all does the audible dash alarm monitor and does it kill the ignition if detecting an issue? My 90 TG is not turning over on the port side and the alarm is full blow so need more info before I start diagnostic back yard style.
Regards,
Shawn

Pretty sure its just an oil pressure alarm, ill look but i think that's the only gauge it runs off

Oil pressure, water temp, trans temp if a trs boat, drive lube if bravo.

the OP said its not turning over, to me means it wont crank, stick is not in neutral ??

Or a bad neutral safety switch

On a 90, there will be two sensors on the engine. Oil pressure that is normally closed, and water temp that is normally open. The alarm you hear is the oil pressure because the engine is not running. Neither one oil or temp will prevent a start. If not the neutral switch, check the start relay on the engine rear by the cannon plug.

WOW !!!! Red guess we never thought of that

It is TRS. I will check the neutral switch and the start relay. Do you know the test for relay using multi meter?
Thank you for your time and responses
Shawn

Check for power to the heavy red wire, if that has power check the small 14ga yellow with red tracer for power with key on and pushing start switch. If that's ok you should have power at the 12 ga yellow with red tracer on the solenoid.
If you do not have power to the 14ga wire, jump the 2 terminals of the neutral switch on the side of the trans together. And try again. Switch is opposite the shift lever.

Well the neutral safety switches are already cut but nicely rolled up and zip tied by previous owner! so as soon as work light charges ill go back out and check the starter relay.