Single continuous guardian tone on 2006 mercury optimax

[Jkovalcik]

I have a 2006 Mercury Optimax 175 and when the motor gets warm after taking it for a ride and I come down to an idle I'm getting a single continuous tone from the guardian system. The tone goes away if I throttle up and I no longer have the tone until I come back down to an idle. I started having this problem after changing my current electronics to a Hummingbird Helix 9 Mega. But so far I have replaced 1 out of my 2 batteries. New water pump and gaskets. New thermostats. The oil reservoir under the hood is full and free of air. I'm out of ideas and would hate to take it to the dealer but I'm worried that's my only option to figure out what's wrong.

 

[alldodge]

Its one of your sensors. Ones which cause prolong alarm are overheat, water pressure, oil pressure. Check the 5V going to the sensors to see if there is a full 5V.

 

[Canufixit2]

OP Wrote "I started having this problem after changing my current electronics to........" I'd remove the Hummingbird and anything else you added/changed before the issue and see if it fixes the issue. Also, I'd check/disconnect/clean all connections in the boat and motor and check voltages.

 

[Jkovalcik]

Do you know the locations of the sensors??

Its one of your sensors. Ones which cause prolong alarm are overheat, water pressure, oil pressure. Check the 5V going to the sensors to see if there is a full 5V.

 

[alldodge]

Unable to find your motor on boat info but here is one which is close. Since it starts when you come to idle I would look at the water pressure first
Item 3 is water pressure and item 5 is overheat

http://boatinfo.no/lib/mercury/manuals/150efi-175efi-200efi.html#/32