BUZZING ALARMS

Jamey Diggs

Jamey Diggs

Member
Jul 15, 2018
44
Merritt Island, FL
Boat Info
270 Sundancer 1999
Engines
5.7 Mercruiser 250HP
Hey gang--1999 270 Sundancer. Mercruiser 5.7 Bravo II. Lots of work done to the engine and ran well all weekend. I was pulling my son on intertube running up and down about 3000 RPMs. When I slowed her down an alarm sounded. Temp and pressure seemed fine (it wasn't the overheat alarm, that sounds different and believe me I've heard that LOL). When I put in neutral alarm went off. Any ideas?
Also, there was a very slight buzzing sound (not an alarm) that seemed to be coming from the cockpit most of the time. Again, I've been through the overheats etc and I know what the alarms sound like. This was not that...just a barely audible buzzing sound.

So really 2 ?s here...thanks for responses in advance
 
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The buzzer connected to the engine that lives behind the dash is only capable of 1 noise. So, if this sounds different , maybe it's your CO detector. Try to pinpoint where the buzzing is coming from
 
It's directly behind the dash...interesting there's only one alarm...the overheat is a high pitched death alarm and definitely sounds different than this one. Maybe CO but no idea why. I don't have a generator or anything. Probably just old and faulty. Interesting it shut off when I switched into neutral. Thanks!
 
I am experiencing this as we speak, I have a 1998 Sea Ray Sundancer, the load buzzing only comes on intermittently when the boat is on plane and it is not a constant buzzing. It seems to only come on when the rpms are over 3500. The buzzing is definitely behind the dash. I keep checking the Oil pressure and Temperature gauges and both are OK. I turn on the blowers and turn on my bilge pumps but the buzzing stays on and there is no water in the bilge. My family freaks out and I have to come back off of plane. When putzing there is no buzzing noise. The buzzing only occurs when the boat is on plane.
 
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There are only 3 senders that can trigger that alarm
overheat..single wire on the t-stat housing
low oil pressure...single wire over by the distributor area
low drive fluid...bullet connectors near the resovoir bottle

Disconnect them 1 at a time to figure which one it is.
 
scoflaw said:
There are only 3 senders that can trigger that alarm
overheat..single wire on the t-stat housing
low oil pressure...single wire over by the distributor area
low drive fluid...bullet connectors near the resovoir bottle

Disconnect them 1 at a time to figure which one it is.
Click to expand...
So if it is not Temp or Oil Pressure, then it must be the Drive Fluid is low...

Thank you, I will check that...But wouldn't that result in a constant alarm ? what I am experiencing only occurs on plane.
 
Switches can fail. Test it like I described. Fuel injected MEFI 3 ?

If you get no joy from those 3. A failing sensor can also be the culprit, At that point you would want to get your ecm scanned.
 
David Koch said:
So if it is not Temp or Oil Pressure, then it must be the Drive Fluid is low...

Thank you, I will check that...But wouldn't that result in a constant alarm ? what I am experiencing only occurs on plane.
Click to expand...

Changing the pitch of the boat can either turn the alarm on or off if the oil level is right at the fill line.
 
Stingrayaxe said:
Changing the pitch of the boat can either turn the alarm on or off if the oil level is right at the fill line.
Click to expand...
It works on oil pressure which has nothing to do with the full line. Your pickup at the bottom of the pan would have to be sucking air to trigger it
 
scoflaw said:
It works on oil pressure which has nothing to do with the full line. Your pickup at the bottom of the pan would have to be sucking air to trigger it
Click to expand...
I should have been more specific. I was referring to the lower unit oil/lube/drive fluid. The lower unit alarm switch can be triggered by the angle of the boat.
 
So I had my mechanic check the (6) relay switches, thankfully the buzzing went away. We test drove several up and down plane maneuvers and there was NO buzzing. We determined it was a loose connection on one of the relays switches. I now know where each of these relay switches is located if the buzzing returns. Easy fix to a very annoying and frightening issue. Thank you for your HELP. Much appreciated. This forum is very useful ! Thank You Again !

NOTE: We checked the all the fluid levels and they all were full.
 
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