Mercruiser 5.7 intermittent alarm

old mate has a Mercruiser 5.7 that sounds an alarm when it is first started at the ramp and then stops once the boat is up and running. It then won't sound for the rest of the day.
It doesn't do it when flushed with freshwater.
He has taken it in for diagnostics twice but they couldn't find any thing wrong. He's now reluctant to hand over any more money for no result.
He's at a loss as what to do next.
Any advice would be appreciated.
Thanks in advance.

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"My greatest problem lies in reconciling my net income with my gross habits"


Posts: 315

Date Joined: 20/01/10

could be

Wed, 2016-02-10 15:49

 Faulty over heat senor or he hasn't been another being caught out by the furuno low battery Alarm

Does he run a furuno ?

Posts: 315

Date Joined: 20/01/10

 Just Google search

Wed, 2016-02-10 16:00

 Just Google search mercruiser 5.7 alarm looks like he's not the first to have that problem

Only read one with someone giving advice to  multimeter the 3 sensors (cooling,transmission and oil pressure) to see which ones causing it

So possibly a faulty sensor

Wilzee's picture

Posts: 93

Date Joined: 10/12/14

thanks for the reply lame. He

Wed, 2016-02-10 16:34

thanks for the reply lame.
He doesn't have a Furuno on board but a good point worth considering.
We can check the sensors with a multimeter, I guess we will need to get hold of a manual to find the sensors and also values we should be looking at.

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"My greatest problem lies in reconciling my net income with my gross habits"

Posts: 80

Date Joined: 10/12/14

 What year is it? Mpi? Or

Wed, 2016-02-10 16:48

 What year is it? 

Mpi? Or carb ? 

Wilzee's picture

Posts: 93

Date Joined: 10/12/14

Dan its 2009 model MPI I

Wed, 2016-02-10 17:53

Dan its 2009 model

MPI I believe

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"My greatest problem lies in reconciling my net income with my gross habits"

Posts: 315

Date Joined: 20/01/10

i guess

Wed, 2016-02-10 16:52

 You would need to multi read whist the alarm is going off ?

This is the one at the top when I Google searched the above but was many more 

 

www.shamrockboatownersclub.com/forums/showthread.php

 

Wilzee's picture

Posts: 93

Date Joined: 10/12/14

thanks lame we will check out

Wed, 2016-02-10 17:55

thanks lame we will check out the link.

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"My greatest problem lies in reconciling my net income with my gross habits"

Posts: 80

Date Joined: 10/12/14

javascript:void(0);/*14551472

Thu, 2016-02-11 07:35

javascript:void(0);/*1455147265211*/ 

 

Have a look here 

 

Wilzee's picture

Posts: 93

Date Joined: 10/12/14

thanks Dan but I cant open

Thu, 2016-02-11 09:17

thanks Dan but I cant open that link

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"My greatest problem lies in reconciling my net income with my gross habits"

Posts: 485

Date Joined: 09/11/06

Hey Wilzee

Thu, 2016-02-11 12:10

have a look at this site
http://boatinfo.no/lib/library.html#
May be of some help
Cheers Paul

Wilzee's picture

Posts: 93

Date Joined: 10/12/14

love your work Paul, found

Thu, 2016-02-11 13:39

love your work Paul, found the service manual on that site.
We will have to have a go at checking for faulty sensors.

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"My greatest problem lies in reconciling my net income with my gross habits"