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Mercruiser Single Beep Only in Reverse

MalloyMalloy Cincinnati, OHPosts: 42Member ✭✭
edited July 2015 in Engine Discussions
I consistently get a single long beep from my 2011 twin 350 mags. I have isolated the beep to the following condition:

port engine in reverse (at roughly idle speed)
straboard engine forward (at roughly idle speed)

It happens every time I dock. I have checked fluid levels, pressure, temps etc...

This season is the first it has happened. I was actually thinking it could be my depth finder??  Is it possible the this combination of engine direction is causing a disturbance in the water that would signal low depth???  Just a thought. I can test this weekend by turning off the depth finder. 

Any other thoughts or advise would be appreciated!


  • SeaHareSeaHare Posts: 140Member ✭✭✭
    edited July 2015
    Mine often does the same thing... IMO, its the sensor in the gear lube monitor that is on the top of the engine. It gets gunked up and causes the float to stick. Ive cleaned it several times and its usally good for a bit but always comes back... now i just ignore it. Ive got carbed 5.7's and the only thing that can cause an alarm is low oil pressure, low gear lube, overheating...
    01 FV 310, 5.7s carbed, B3s
  • Michael TMichael T Posts: 6,383Member ✭✭✭✭✭
    That's a good call SeaHare. may I add a suggestion? Be careful when cleaning that float inside the gear lube reservoir. Most of them are held onto the fixed SS pin they travel up and down on by a SS "C" clip. If that pops off you can't get it back on and have to order a new reservoir - as I found out. Clean away but be careful not to snag that friggin' clip!
  • MalloyMalloy Cincinnati, OHPosts: 42Member ✭✭
    If the sensor needs cleaned wouldn't it go off at other times as well. It is very specific when it alarms. Could it be a vibration issue?  I will clean it and report back. Do you recommend simply wiping it clean?  Anything else I should be checking?
  • 212rowboat212rowboat Posts: 2,116Member ✭✭✭✭✭
    I bet if you pulled codes you'd find a knock sensor tripped.  

    The engine, while going into or out of gear, momentarily cuts ignition as it doesn't have any other way of dealing with stall... Pretty slick design... The other engine running and that one momentarily stalling as it should likely has just the right bounce to it to announce itself as a knock, then quickly change its mind when ignition is re-applied... 

    For this to be reasonable, it'll have to be doing it just as soon as you touch neutral or reverse.... Is that when it happens? 
  • MalloyMalloy Cincinnati, OHPosts: 42Member ✭✭
    No it takes 15-30 seconds before the alarm sounds. Everything feels as if it is functioning normally. Just get the long beep 1 time. 
  • 212rowboat212rowboat Posts: 2,116Member ✭✭✭✭✭
    Well I'm out of spitwads now... 
  • MalloyMalloy Cincinnati, OHPosts: 42Member ✭✭
    Ha!  Thx for the thought. 
  • Dream_InnDream_Inn Annapolis, MDPosts: 4,551Member, Moderator mod
    Could be a shift sensor.  I have a sensor right now that is a bit 'sticky'.  I have VV7, so it immediately tells me that is what it is.  My mechanic said he'd change it next time I get some service done.

    Dream 'Inn III -- 2008 400 Express

  • SeaHareSeaHare Posts: 140Member ✭✭✭
    I just clean the drive lube monitor with brake cleaner... dump the lube.. spray liberally into the resivoir....refill
    01 FV 310, 5.7s carbed, B3s
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