My buzzers will sound off for a long time with out stopping, fluids all check out fine and temp as well, if I turn off the engines after running for a few minutes when I turn them back on they usually stop. Any ideas? This is on a 1991 Formula standard Merc / Bravo setup.

Does this happen wen on plane running wot or just when crusing???

It is at start up I get it to go away before I leave the slip. It never happens while I am driving. It will continue to buzz if I dont get them off while running.

The buzzer alarm operates by a sensor grounding for low temp, low oil pressure, low fluids, etc.
You'll need to find out which sensor is grounding to find the problem.
At startup the low oil pressure sensor will usually be the ground. Is your oil pressure at idle ok?

Yes it is around 50 to 60.

Whay do they stop after turning them off and on several times?