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Message |
    
Brian Seib
New member
Username: bgseib
Post Number: 1
Registered: 07-2009
| | Posted on Sunday, July 12, 2009 - 10:41 am: | 
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Good morning.. I recently purchased a boat with a 2000 volvo penta 5.0 carb injected. When purchased the boat ran about 170 or so which I would assume is normal. I took it to a boat repair center, and had the oils change, impellar, and lower oils changed. They said the impellar was all broken up, and had to snake it out. Since that time I the temp only gets to about 115 - 125, and now it is seeming to bog down when I go to take off? So I was guessing that the thermostat may be bad, so I was thinking I would change it out, but wanted to know can I just get one at an autoparts place or is it a special maring grade of some sort? Or am I looking the wrong direction of what to change out? Thanks,
Brian |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4637
Registered: 02-2006
| | Posted on Sunday, July 12, 2009 - 12:56 pm: |
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I would only use an automotive thermostat if the engine had a closed cooling system; but if it is raw water cooled, the safest thing to do is get the proper thermostat either from VP or a Sierra or other aftermarket equivalent. Not sure if the one below is your model, but thermostats generally cost around $25.
http://www.volvopentastore.com/Circulation_Pump_and_Thermostat/dm/cart_id.753280 878--session_id.271311432--store_id.366--view_id.322342
Before buying anything, you may want to check the thermostat by introducing it in hot (close to boiling) water, then cool it and make sure it opens and closes with the temperature changes.
Also, the problem could be caused by a corroded thermostat housing and not by the thermostat itself. |
Brian Seib
New member
Username: bgseib
Post Number: 2
Registered: 07-2009
| | Posted on Sunday, July 12, 2009 - 03:44 pm: |
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El Pescador - thank you VERY much for your reply. I went ahead and pulled the thermostat housing after my last post, and was going to take the thermostat to the auto parts store to compare, but after reading your post - figured I will wait, but looks like the thermostat is actually part of the house, or does the O Ring actually hold the thermostat in? AND on another note - I found some pieces of the old impellar in the #14 hose on the diagram. Could this have caused this problem, or just a coincident? I appreciate any help |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4639
Registered: 02-2006
| | Posted on Sunday, July 12, 2009 - 04:11 pm: |
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The thermostat is independent from the housing, you should be able to pull it out with the o-ring.
Hose 14 is the delivery from the raw water pump, so stuck pieces of rubber in that hose would actually contribute to low water flow and higher (not lower) water temperature.
I suspect you will find a piece of impeller stuck in the thermostat. |
Brian Seib
New member
Username: bgseib
Post Number: 3
Registered: 07-2009
| | Posted on Sunday, July 12, 2009 - 05:11 pm: |
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OK - it gets strange now. I took the thermostat out, and it does not have anything stuck in it, and it is actually closed. I tested in hot water and it open/closes at close to boiling point as it should I am guessing. So now I am really lost?? Also - when the therm stat opens I guess it dumps the water into the exhaust? Any other thoughts as to what would make it run cool? |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4641
Registered: 02-2006
| | Posted on Sunday, July 12, 2009 - 05:22 pm: |
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Check that the thermostat housing is not corroded/perforated. |
Brian Seib
Member
Username: bgseib
Post Number: 4
Registered: 07-2009
| | Posted on Sunday, July 12, 2009 - 06:32 pm: |
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I will check it - the therm is definitely old looking, so I will get one from the marine shop tomorrow anyway then put it back together I guess and hope for the best unless anyone has any other ideas..
Thanks,
Brian |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4642
Registered: 02-2006
| | Posted on Sunday, July 12, 2009 - 06:53 pm: |
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If the thermostat housing is 9-10 years old, I think it is also becoming due for replacement.... |
Brian Seib
Member
Username: bgseib
Post Number: 5
Registered: 07-2009
| | Posted on Sunday, July 12, 2009 - 09:53 pm: |
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ya - I agree. I am not sure if this is original, but it sure looks it Thanks for all your hellp... |
Brian Seib
Member
Username: bgseib
Post Number: 6
Registered: 07-2009
| | Posted on Monday, July 13, 2009 - 12:15 am: |
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OK dumb question I am assuming there is only one thermostat? when you take the housing off - it sure looks like there is room for one between the housing and the block just like a car block. Probably a dumb question... |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4644
Registered: 02-2006
| | Posted on Monday, July 13, 2009 - 01:25 am: |
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Just one thermostat. |
Brian Seib
Member
Username: bgseib
Post Number: 7
Registered: 07-2009
| | Posted on Wednesday, July 15, 2009 - 12:16 am: |
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Well - took it out on the lake today, and all looks good on the temp!!! Thanks!!! The puttering on giving it throttle was still bad at the start, but got better as the trip went on. I am hoping it is just burning out some residue or something.. I may change the plugs out anyway in case they are fouled or anything.. Thanks for the help.  |
