120HP Thermostat spring

PaulO

Petty Officer 1st Class
Joined
Jan 25, 2010
Messages
225
I couldn't manage to get my hands on a thermostat spring for the 1991 120HP Force. There are two types. I think I needed the red spring.

1. What is the purpose of the spring?

2. Can I use any old spring that fits?
 

foodfisher

Captain
Joined
Feb 18, 2009
Messages
3,756
Re: 120HP Thermostat spring

If I'm right, the spring is what opens and closes the valve. It expands and cotracts with temp. variations.
 

PaulO

Petty Officer 1st Class
Joined
Jan 25, 2010
Messages
225
Re: 120HP Thermostat spring

Have a look at part number 4 Here

I am not typing about the thermostat itself.

P
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: 120HP Thermostat spring

If I remember correctly there is a rubber seat in a steel ring that sets into the block. then the thermostat sets in and the spring behind the therm. when the cover is installed the spring pushes against the therm. The spring holds the thermostat against the rubber gasket. I suppose it can also release in case of overpressure but I doubt that would ever happen. I also suppose any stainless spring with a similar pressure rating would do
 

PaulO

Petty Officer 1st Class
Joined
Jan 25, 2010
Messages
225
Re: 120HP Thermostat spring

Does anyone know the rating of this spring?

Is the order in the parts diagram the order of installation in the housing?
 

jayjones72

Cadet
Joined
Mar 3, 2010
Messages
27
Re: 120HP Thermostat spring

Would you let me know if you find that spring?
I will do the same.as I am trying to find one
 

DavidW2009

Petty Officer 1st Class
Joined
Sep 12, 2009
Messages
272
Re: 120HP Thermostat spring

Spring rating is determined by the following parameters:

Outside diameter
Wire diameter
Free Length
Solid Height
Number of coils
Total deflection
Material (probably 302 or 316 stainless steel)

If you match the above criteria from an OEM spring, should be able to obtain a new replacement with a load rating that's close.

Or if the load rating, O.D. and deflection are known, a suitable spring can be selected.

www.centuryspring.com

www.diamondwire.com
 

jayjones72

Cadet
Joined
Mar 3, 2010
Messages
27
Re: 120HP Thermostat spring

So I called mercury this morning. Talked to a tech who said that the red spring which is NLA had a measurement of 3.02 ( can't remember what this measurment was but he seemed to think it was the only difference)and the other spring that is available had a measurement of 3.20 so not a drastic difference of.18 he said the 3.20 spring should work just fine. I hope this helps. Or you could give them a call for more details. I ordered the other spring and will be using that one
 

PaulO

Petty Officer 1st Class
Joined
Jan 25, 2010
Messages
225
Re: 120HP Thermostat spring

jayjones72

So is that part number F664268 on the boats.net site??? I just ordered two lots from the States and they have arrived in Australia.

When you get the spring you might be able to detail its diameter , resistence etc and I will see if I can pick something up is Oz.
 

jayjones72

Cadet
Joined
Mar 3, 2010
Messages
27
Re: 120HP Thermostat spring

yeah thats the one.
I ordered it yesterday and it has been shipped so hope to have it by this weekend. I will be happy to let you know about it when i get it good luck with yours i hope this works.
 
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