Reply
 
Thread Tools Search this Thread
 
Old 19 June 2013, 07:51   #1
Member
 
Phil M's Avatar
 
Country: UK - England
Town: Whitehaven
Boat name: Pegasus
Make: Zodiac Pro 530
Length: 5m +
Engine: 115hp Merc 4st
Join Date: Oct 2012
Posts: 337
Mariner 75 2st Warning beep

I'm hoping somone can offer a sugestion on an intermittent problem I have on my 1988ish Mariner 75 clamshell. The engine seems in good condition and starts, runs, idles very well however the first time I took it out we got a continuous warning tone after short run. It came and went but the teltale was weak so we limped back to harbour and I ook it home and replaced the impeller and flushed out the cooling pipework as there was a blockage at the teltale exit point where we had picked up some silt. The next run out was fine, no warnings, teltale flowing like a pressure washer. Last weekend we went out again and again the teltale was fine, but whilst idling in the harbour lock the beep came back for a short while before fizzling out again. As the oil level was good, teltale very strong and beep had gone, we carried on with the trip with no further warning beeps. It ran at idle for a while afterwards on the muffs with again no warnings.

So, my question is (finally) what coudl be causing this? Genuine overheat due to internal blockage? Faulty temp or oil sender? Is there anything else that these engines warn of or is this a common "quirk" of these engines?

Any suggestions appreciated!

Phil M
__________________

__________________
Phil M is offline   Reply With Quote
Old 19 June 2013, 07:57   #2
Member
 
Country: UK - England
Town: Isle of Wight mostly
Make: Regal
Length: 6m +
Engine: Mercruiser
MMSI: 235911246
Join Date: Oct 2012
Posts: 188
Could be a problem with thermostat, have you replaced that yet?
__________________

__________________
solent spence is offline   Reply With Quote
Old 19 June 2013, 10:23   #3
Member
 
Phil M's Avatar
 
Country: UK - England
Town: Whitehaven
Boat name: Pegasus
Make: Zodiac Pro 530
Length: 5m +
Engine: 115hp Merc 4st
Join Date: Oct 2012
Posts: 337
Not yet. I'll see what I can get hold of and give it a go.

Phil M
__________________
Phil M is offline   Reply With Quote
Old 19 June 2013, 11:14   #4
Member
 
Country: UK - England
Town: Isle of Wight mostly
Make: Regal
Length: 6m +
Engine: Mercruiser
MMSI: 235911246
Join Date: Oct 2012
Posts: 188
Sounds very similar to a buzzer alarm I had on a 175 merc, which had same symptoms and ended up being down to the 2 thermostats on that engine.
__________________
solent spence is offline   Reply With Quote
Old 22 July 2013, 13:18   #5
Member
 
Phil M's Avatar
 
Country: UK - England
Town: Whitehaven
Boat name: Pegasus
Make: Zodiac Pro 530
Length: 5m +
Engine: 115hp Merc 4st
Join Date: Oct 2012
Posts: 337
I finally got round to looking at this again and have had the thermostat out and done the hot water dunk test. The inner spool lifted by about 6mm and completely compressed the spring in just boiled water, so it seems to be functioning. The waterways look a bit scaled up but largely clear of debris. I did notice the popper valve seems quite firmly in its hole. As a test I pulled it out then placed it over the hole (just inside) then put the cover, spring etc back on. The spring doesn't have enough strength to push the valve back in so i'm guessing it is too damp tight and won't push out under water pressure. Could this be the problem? Recent trips out saw the alarm on on tick over and on higher revs but quiet in mid throttle.

Phil M
__________________
Phil M is offline   Reply With Quote
Old 22 July 2013, 14:01   #6
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Could well be-is the grommet swollen?
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 22 July 2013, 17:00   #7
Member
 
Phil M's Avatar
 
Country: UK - England
Town: Whitehaven
Boat name: Pegasus
Make: Zodiac Pro 530
Length: 5m +
Engine: 115hp Merc 4st
Join Date: Oct 2012
Posts: 337
it looks ok with no damage but I don't know what the inner diameter should be. it could well have swollen slightly making it a bit of a tug to remove the poppet. I assume the poppet should slide quite easily. I will try to pull it out tomorrow and take a better look then see if I can get a new set of parts.

thanks,

Phil M
__________________
Phil M is offline   Reply With Quote
Old 22 July 2013, 17:04   #8
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Mine on the 225 touches-but easy to get in and out. I'd replace the spring, gaskets and grommet.Just did mine, and it's not expensive.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 26 August 2013, 05:36   #9
Member
 
Phil M's Avatar
 
Country: UK - England
Town: Whitehaven
Boat name: Pegasus
Make: Zodiac Pro 530
Length: 5m +
Engine: 115hp Merc 4st
Join Date: Oct 2012
Posts: 337
Ok, I've replaced the thermostat, gaskets, poppet, spring, grommet and engine block liner (which took a beating to fit!). Ran it out yesterday and the problem is still the same. I know that the poppet is working because I put a thin piece of wire through the cover breather as an indicator and I can feel it open under higher revs, although it seems to bounce around a bit. The thermostat opens in hot water and I know it pumps well up to the thermostat. The problem starts with a beep at tickover, which is initially cured by revving the engine, presumably opening the poppet. After a while though the beep is constant regardless of engine speed. My next port of call is the sensor. Trouble is, I cant get it out. I've removed the plastic retainer and given it a pull but the only thing to hold on to is the cable and I'm concerned about ripping it out of the back of the sensor and ending up with a broken sensor stuck in there.

Anybody know how to get these out? Also, does anybody know what temperature the sensor is supposed to go open circuit? I'd like to check it before I shell out for a new one.

Thanks,

Phil
__________________
Phil M is offline   Reply With Quote
Old 26 August 2013, 08:45   #10
Member
 
Country: UK - England
Town: bicester
Length: no boat
Engine: outboard only
Join Date: Feb 2009
Posts: 894
Just a note on testing thermostats, if you look on the btm of the wax (the bit in the middle) you should see a number usually 60 if its not there look else where on the thermostat, that is the temprature that it should open.If you put the thermostat in near or boiling water , you have either buggered it or damn near buggered it. If you have a thermometer in the water and the thermostat opens on or near the correct temprature did it open smoothly , and when removed from the water close smoothly if it did its a good un, if it didnt throw it away.
__________________

__________________
uncle al is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 20:44.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.