9.9 termostat(1983)

raczekp1

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Mar 30, 2010
Messages
1,327
hi.
In the past i changed termostat in my motor.
i put new termostat and all staf(spring, cap, rubber bushing, gasket)
i just but it back as it was mounted before.
im thinking if this spring is nesesery?
while puting back terostat cover i had to keep this very careful and tight, becouse spring want to lift back termostat cover while puting bolts.
so maybe this spring will not allow to open termostat?
here is a link to view:
http://www.boats.net/parts/search/BRP/JOHNSON/1983/J10RCTR 1983/CYLINDER & CRANKCASE/parts.html
 

jasper60103

Commander
Joined
Sep 18, 2008
Messages
2,055
Re: 9.9 termostat(1983)

hi.
In the past i changed termostat in my motor.
i put new termostat and all staf(spring, cap, rubber bushing, gasket)
i just but it back as it was mounted before.
im thinking if this spring is nesesery?
while puting back terostat cover i had to keep this very careful and tight, becouse spring want to lift back termostat cover while puting bolts.
so maybe this spring will not allow to open termostat?
here is a link to view:
http://www.boats.net/parts/search/BRP/JOHNSON/1983/J10RCTR 1983/CYLINDER & CRANKCASE/parts.html

Yes, that spring is required. It holds the thermostat in place, and it does not interfere with it's operation.
 

raczekp1

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Mar 30, 2010
Messages
1,327
Re: 9.9 termostat(1983)

i'm asking becouse my previus motor:Jo 6hp/1973y had termostat with oring but there wasnt any spring betwen termostat cover and termostat.
 

jasper60103

Commander
Joined
Sep 18, 2008
Messages
2,055
Re: 9.9 termostat(1983)

i'm asking becouse my previus motor:Jo 6hp/1973y had termostat with oring but there wasnt any spring betwen termostat cover and termostat.

Oh, ok. For what its worth, my '87 30hp has a spring too.
 

OptsyEagle

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Sep 13, 2006
Messages
1,365
Re: 9.9 termostat(1983)

i'm asking becouse my previus motor:Jo 6hp/1973y had termostat with oring but there wasnt any spring betwen termostat cover and termostat.

Just different designs. You need the spring in yours.
 

dazk14

Ensign
Joined
Jul 22, 2008
Messages
966
Re: 9.9 termostat(1983)

The spring is an improved design compared to the spring-less design on the earlier copies of that motor. The thermostat still functions (opens/closes) AND at higher speeds and water pump pressure the thermostat will lift off its seat to provide additional cooling water.
 

raczekp1

Lieutenant
Joined
Mar 30, 2010
Messages
1,327
Re: 9.9 termostat(1983)

hi.
i'm concerning about force caused by spring.
i put new spring, and it holds quite well.
so water pump must do high presure to push water even when termostat lift upper part
 

dazk14

Ensign
Joined
Jul 22, 2008
Messages
966
Re: 9.9 termostat(1983)

If you bought the correct spring, it will work properly as long as your water pump is good. Ensure you have a good stream from the tell-tale.

The thermostat begins to open at ~140degrees F., fully open~160degrees F. and previous versions of your motor did not have a spring and cooling water could only flow through the open thermostat - but some motors tended to run too hot - even when the thermostat was completely open.

Your design ensures enough EXTRA cooling at higher speeds and I've seen them run full throttle ~140degrees where the older versions might be 165+deg. properly set-up. Factory Max is 173deg as I recall.

Hope this answers your question.
 
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