6.5 onan
Moderators: BeaconMarineBob, Moderator, BeaconMarineDon
A motor running without t-stats is not efficient among other things. Having said that, I've seen Onans running for years without them. People usually don't replace them due to expense or a misdiagnosed condition. Personally, I wouldn't run without them. Why are they being removed, what are the symptoms?
She was a 1969 36 ft wooden beauty with big blue 440s that we'll miss forever.
And thanks to the gang, 2012 Trojan Boater Of The Year
And thanks to the gang, 2012 Trojan Boater Of The Year
not to hijack this post,
but i ran across this as an option to the expensive onan oem thermostat part #309-0130 for the 6.5 mccck
i found 2 references on the internet stating the yanmar part#105582-49200 themostat is interchangeable with the onan. i found costs $24.00 each instead of $50 or so for the onan. has anybody substitued this or similiar in the mcck series
but i ran across this as an option to the expensive onan oem thermostat part #309-0130 for the 6.5 mccck
i found 2 references on the internet stating the yanmar part#105582-49200 themostat is interchangeable with the onan. i found costs $24.00 each instead of $50 or so for the onan. has anybody substitued this or similiar in the mcck series
1997 CARVER 405
"the BLACK PEARL"
past fleet
1978 F32 SEDAN CHRYSLER 318's
current fleet
1997 seadoo gts
1997 yamaha wave venture
1985 sunbird 18 ft runabout
1968 coronado sailboat 25 ft
sunfish
14' hobie cat
canoe
8ft portabote
"the BLACK PEARL"
past fleet
1978 F32 SEDAN CHRYSLER 318's
current fleet
1997 seadoo gts
1997 yamaha wave venture
1985 sunbird 18 ft runabout
1968 coronado sailboat 25 ft
sunfish
14' hobie cat
canoe
8ft portabote
- Diverted Income
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Re: 6.5 onan
Would be nice if someone could confirm the Yanmar p.n. I may need to track one down and compare if not. Onan is stupid high.
1982 Trojan F-32 w/Merc 230's
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
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Re: 6.5 onan
here is a picture of the yanmar one, compare;
http://www.swdieselinc.com/Yanmar_Therm ... -49200.htm
http://www.swdieselinc.com/Yanmar_Therm ... -49200.htm
Larry Eddington
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
- Stripermann2
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Re: 6.5 onan
Like Larry stated...take a look and decide for yourself. They look close enough to me, to work.
But there is also another Onan thermostat, a 140-145 degree which is part number 309-0130.
Yanmar Thermostat;

Sierra Thermostat; You can get at Worst Marine under number, 13480579 and Sierra number, 23-3606

But there is also another Onan thermostat, a 140-145 degree which is part number 309-0130.
Yanmar Thermostat;

Sierra Thermostat; You can get at Worst Marine under number, 13480579 and Sierra number, 23-3606

Jamie
1985 F-32 270 Crusaders
1988 Sea Ray 23 350 Merc.
Trojan. Enjoy the ride...
-I don't wanna hear anyone whine...Anymore!
-You might get there before me, but you still have to wait for me, for the fun to start!
1985 F-32 270 Crusaders
1988 Sea Ray 23 350 Merc.
Trojan. Enjoy the ride...
-I don't wanna hear anyone whine...Anymore!
-You might get there before me, but you still have to wait for me, for the fun to start!
- Diverted Income
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Re: 6.5 onan
Yup - I need the 140* stat as mine is keel cooled
1982 Trojan F-32 w/Merc 230's
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
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Re: 6.5 onan
I went ahead and sprang for the Onan ones for mine, not installed yet but have them as backup also points and plugs. Right now my Genny just hums so will leave alone. 

Larry Eddington
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
- prowlersfish
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Re: 6.5 onan
keel cooled ? Are you sure ?Diverted Income wrote:Yup - I need the 140* stat as mine is keel cooled
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat

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Re: 6.5 onan
Parts manual shows it should have a 140* stat if it is (keel cooled) raw water cooled. 180* if fresh water cooled, two different p.n. 309-0130 vs 309-0289. Onan MCE. Am I missing something? (probably am) 

1982 Trojan F-32 w/Merc 230's
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
- prowlersfish
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Re: 6.5 onan
You maybe raw water cooled (uses lake/bay water ) or fresh water cooled ( antifreeze w/ heat exchanger)
But I highly doubt You are keel cooled . A keel cooler uses coolant flowing through tubes or a exchanger that is mounted under the hull in the water . As a general rule they are not used on Planning hulls .Its a safe bet that Trojan never used them on a F32 .
But I highly doubt You are keel cooled . A keel cooler uses coolant flowing through tubes or a exchanger that is mounted under the hull in the water . As a general rule they are not used on Planning hulls .Its a safe bet that Trojan never used them on a F32 .
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Last edited by prowlersfish on Fri Dec 27, 2013 8:47 pm, edited 1 time in total.
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat

Re: 6.5 onan
Two completely different things!Diverted Income wrote:....(keel cooled) raw water cooled......
She was a 1969 36 ft wooden beauty with big blue 440s that we'll miss forever.
And thanks to the gang, 2012 Trojan Boater Of The Year
And thanks to the gang, 2012 Trojan Boater Of The Year
- Diverted Income
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Re: 6.5 onan
Guess I figured (wrong) 140* so it would not precipitate the river crud into the water jacket if cooler than the 180* I am wrong again. Thanks for the explanation. Still on the search for the stats though!
1982 Trojan F-32 w/Merc 230's
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
- prowlersfish
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Re: 6.5 onan
I added keel cooler pic to my post above
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat

- Diverted Income
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- Joined: Wed Nov 28, 2012 8:18 pm
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Re: 6.5 onan
So what would you guys recommend 140* or 180*??
Thanks!
Thanks!
1982 Trojan F-32 w/Merc 230's
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat
1975 Baja V-1800J w/ 502 Ford
http://missriverrat.com
https://www.facebook.com/UMRMriverrat