Mariner 60hp constant buzzer over heating

[Cinarli]

I have a problem with my mariner 60hp oil injected mid 90's outboard. After I run it for a while, about 10 min on idol, it starts buzzing constantly, I have had the motor for over 2 years it does this all the time. I have taken it to 2 different machanics, had the impeller changed and it still does it. When I start going and get to plane it stops and when I start idoling or going very slow,after about 2-3min it will start buzzing again. Ussualy it pumps water out but its very hot and sometimes it will stop pumping altogether.
Has anyone had a simular problem to this or heard anything of this nature.
Thanks guys.

 

[Texasmark]

Re: Mariner 60hp constant buzzer over heating

Guess what mate. My current engine was purchased used and I did not take it for a water test prior to purchasing.

On my first outing I had exactly the same problem. A solid alarm is over temp. The horn quit after a minute or so when I planed out but returned just like yours when I slowed down.

Your thermostat is stuck shut!!!!!!!

Pop the cowl and get behind the engine and look at the water jacket over the pistons (the sparkplugs are installed in it). Up in the left corner (on my 90, yours may be in a slightly different location, and shaped differently) is a cover (roughly .5" x 2.5") with 2 bulges in it and 2 screws holding it on.

Removing this cover reveals your high speed bypass (the large bulge) valve, and your thermostat (smaller bulge). The high speed bypass is obviously working fine as your horn went off once you got adequate water pressure into the engine. Just concentrate on the stat.

The stat is stamped with the correct opening temp, like 143F for mine. They usually stamp the pellet bottom.

I was careful when removing the cover and didn't do too much damage to the gasket on the cover so I reused it when closing back up and applied blue RTV silicone as needed. Works fine.

Today is your day........I just made it for you and thrilled to be able to do it.

Mark

 

[Cinarli]

Re: Mariner 60hp constant buzzer over heating

Mate you are a blessing, you just helped me with 2 problems in half an hour.
May every thing you touch turn to gold.
You have just made may year not just day.
I hope that is the problem, it sure sounds like it.
I really dont know how to thank you, because that sounds better than anything anyone has suggested so far.
Thank you, Thank you, Thank you.

A very happy Auzzy

Now I can go to sleep with ease, seriously.
Very kind Regards,

Adam

 

[Cinarli]

Re: Mariner 60hp constant buzzer over heating

I opened the thermostat and found only one bulge. From what I researched on the thermostat, the bulge I have is the Large bulge which would most likely be the high speed bypass. I think it is missing the thermostat bulge. On ebay I looked for the thermo and it doesnt look anything like the bulge thats in there.
Now I'm totally lost. Please help.

Thank you

Adam

 

[Faztbullet]

Re: Mariner 60hp constant buzzer over heating

Depends on which 3 cylinder engine you have, if you have the small bore crossflow it does not t-stat and if its the looper engine you have a "poppet" and t-stat. The looper engine has oil tank under cowling....

 

[Cinarli]

Re: Mariner 60hp constant buzzer over heating

Firstly, thank you for reply, The cowl has hole on top for where you put oil.
So you dont have to open cowl to put oil.
so that would mean looper engine is that right.

 

[Cinarli]

Re: Mariner 60hp constant buzzer over heating

I looked up ebay and the Poppet Valve Kit is exactly like my one.

 

[Faztbullet]

Re: Mariner 60hp constant buzzer over heating

Look at link below.....
http://www.mercruiserparts.com/Show...1&bnbr=150&bdesc=CYLINDER+BLOCK+AND+CRANKCASE