Need some help.

I have an alarm going off when I start my engines (twin 1997 HP500 carbs). All of my gauges are reading normal, and I have not changed anything. The alarm will keep sounding until I get the boat out of the harbor and up on plane. Once I get going, the alarm stops. However, when entering back into the harbor (idling for ~2 minutes) the alarm started sounding again.

I run the blower for 3-4 minutes before starting. Engines starting and performing fine (maybe a little rich if anything).

The only difference is that we have been hit with some very hot and humid weather here in Chicago. This never happened last year and did not start until last week... once again, only when the hot humid weather hit.

Any ideas as to what this could be? Fumes?

Yes, I know I can rip out the wire to make it stop! Not the solution I am looking for.

Thanks!

Check that the gear oil bottles are filled to the line.

Check that the drive oil bottle(s) are filled to thr line.

Gear Oil bottle first.....

My Fountain did the same thing after a drive oil change , one bottle was low and causing the alarm...

If I had an alarm going off, I would certainly NOT be bringin' her up to plane to make it go away. . . .
It's most ALWAYS gonna be low fluid in some reservoir or other.

I have several bottles of gear lube in the truck and will check the levels tomorrow. I had eyeballed them a couple of weeks ago, but admit I may have rushed past a good inspection.

Thanks for the help!