THERMOSTAT OR NO THERMOSTAT ?

[Reel-Job]

Hi All
Can anybody give me some advice on weather i should put my thremostats back in my 1997 150Hp Offshore Mercury.Last weekend my motor overheated or should I say the Alarm went of so I shut the motor down and noticed the tell tail was still pumping water out just .I thought it was a sticking thermostat so I slowly went back to the ramp without the alarm comming back on.Yesterday I removed the thermostats and put them in hot water and they worked fine.So I pulled the gearbox of and replaced the impeller which only had 2 fins left.When I started the motor it pumped water out like it never has before :o,but I had no thermostats in yet,so i put them in and now it only has a little stream comming out.I let it run for 15 minunits till the thermostats opened and it made not much differents in the stream of water.Do we need them in or not in Australian Conditions. ???
THANKS ALL
Lou
Reel-Job

[aido]

i did a little research on cooling systems not long ago.
thermostats reduce engine wear at low rpm's it seems.

actually the only schematic diagram i could source was
the cooling system of a mercury 150 efi.
it indicated no flow from the tell tale untill the thermostats
started to open. confirmed this with a mate who has one.

do a little search here. it might interest you.
http://www.ausfish.com.au/cgi-ausfish/board/YaBB.cgi?board=Boats;action=display;num=1088670410 ;start=0
cheers, aido.

[Payneful]

Did you manage to find the other bits of the impeller. Had a problem once where little bits of the impeller had gotten caught in the cooling water galleries. Engine always overheated when skiing etc (steam coming off the tell tale). If it has blocked a particular gallery it could cause a hot spot in the head and this could lead to other problems

Just a thought

Sam.

[Reel-Job]

Thanks for that Aido [smiley=2thumbsup.gif]
This is what I like about this site lots of people ready to give a hand and Offer some good advice for people who need it.I might put them back in and try it out at Bribie on saturday morning.I will let you know how it all goes. ;)

[Payneful]

Oh and as far a putting the thermostat back in ... i would recommend it. Cold engines don't run as efficient and aido said can cause excessive wear.

Sam

[Reel-Job]

Hi Sam
I did find the 3 fins that broke off ,and i had a good look at the water pump housing to see if there was any grooves as well.could not find anything else.
Regards Lou
Reel-Job

[ba229]

My 15Hp (ALOT smaller than yours, i know :-) ) has no thermostat and when i rang the outboard repairers for a price they told me they always take them out anyway cause they just corrode and our waters aren't cool enough to worry about them.

still running fine without one :-)

[searaider]

Interesting topic ,
MMMMMMMMMMMM to leave them out ,or put them back in ?
If the mighty Reel-Job performs OK on Saturday , I'd leave them in .With the forcast you probably wont be able to go over 10 knts to try the motor out . ;)

Peter
Searaider 2

[SeaSaw]

Reel Job,

I have been told that if you do want to remove the thermostat that you should cut the centre out and leave the housing installed. The housing actually restricts some of the water flow even when the thermostat is fully opened.

Mark

[bungie]

This issue of bush and beach has a write up on just this subject

[Fin_Addict]

Put them back in mate.. Speaking from my trade background you'd be mad to leave them out..

[noluck]

I got friend outbord mech. and he say to me once ther use to pull them out befor instoling motor on boat. in (mercury)
I know on suzuki u must have termostart. :-[ :-[

cheers
no_luck

[ANYFISH]

i talk like that after about 16 rum cans in 3 hours

[Reel-Job]

Thanks everone!
I will put them back in on the weekend and go for a run to the Banks.
Noluck ??? What the!
I CAN SEE WHAT YOU MEAN [smiley=dizzy.gif] [smiley=dizzy.gif] [smiley=dizzy.gif] [smiley=hammer.gif] [smiley=huh2.gif] [smiley=huh2.gif] [smiley=hammer.gif] [smiley=hammer.gif] iI THINK ???????