Big vacuum leak?

Leaky Rear

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Aug 31, 2017
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So I scraped off the gasket material , from the housing face - Cleaner and dry in theses pics . The parts , spring and plunger i believe were the old thermostat. Seems the last one I replaced was easier , thought it would just sit in the block and housing bolt over. I do not see a way to remove this metal stuff. Have I ruined the thermostat housing?
 

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muc

"Retired" Association of Marine Technicians...
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use a sharp o-ring pick to remove the rubber o-ring that holds the thermostat in.
 

Grub54891

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Looks to be stuck pretty good. You have not ruined the housing. Amtech is probably right, also the stat is shot anyway, just break apart the remains and clean it out.
 

Leaky Rear

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Thanks muc and grub I'd forgot the O ring. Looks to be a 160 degree thermostat .
My concern is the sensor didn't sound when the motor got hot. I will put together. and see where it gets me.

We are getting freezing temps, I am about to cover and store for winter. (head and block freeze plugs n battery out)
Goal is to test , and post if it works.
 

Leaky Rear

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Do I ask NAPA for a 160 degree for 305 chevy, Is this special marine or standard thermostat?
 

Lou C

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You need a marine stat (standard OMC/Volvo 160* stat) an auto stat will not last in raw water cooling applications. Dig out that rubber ring and clean out the housing. Make sure the bypass hole is open and the feed holes for the impeller hose and manifold hoses should be rodded out with a coat hanger wire. If you can clean it up fine but if you see chunks of cast iron flaking off I'd replace it. I found that in salt water I replace those about at the same time as manifolds & elbows, at 6-7 years or so.
 

Leaky Rear

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Darn , they insisted it was regular small block 305 thermometer . Of course did not fit.
So about 2 hours 20 minutes bucks in gas for a 7 dollar part.

What can u expect from and unskilled person making peanuts!
Should have read this AM , before leaving
 

Leaky Rear

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Ive been to NAPA , O 'Riely and Autozone. All claim to have the "marine thermostat.

But I'd been sold the street chevy camera 1985 pn#183551.

What they are selling meant to set on the intake and bolt the housing on top.
My housing is narrow , the camaro thermostats all was to big - none fit into the housing they are too wide - can not recess into the housing.

No O ring is the first clue , provided with the thermo in the box.
Spent 30 bucks on gas.

No thermostat , rain coming . Run NOTHING?

What are chances in warm CA summer the thermostat not needed. i want to bolt together to see if the obstruction to water flow is in the thermostat . Without one I will know , and can proceed with dirt intake and cylinder fogging .

Can I for test purposes do this, eliminate the thermostat , to see if problem so I can cover the thing for the rain.
E bay , amazon ? At least i can make them eat the cost when it comes wrong over again.

Do Ii really need the thermostat for general operation May through September , 80 to 100 degree days?
 

Lou C

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Find a boat dealer who sells Volvo Penta parts or an Evinrude dealer that sells OMC Cobra parts, the housing and stat are standard OMC items before Volvo bought out their sterndrive operation. Forget the auto parts stores, they don't know their azz from a hole in the ground when it comes to boats.....I've got 3 dealers within 5 miles of me where I could get that...I would not run it without a 'stat...
 

Leaky Rear

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Aug 31, 2017
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Very good advice. I found a boat repair that will order the correct one. The auto parts guys tried .
Was barking up the wrong tree.
 

Leaky Rear

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Aug 31, 2017
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Got the right stat... the boat dealer found a piece of rubber impeller from raw water pump blocking a riser hose office in stat housing.
So I need a new raw water pump again.
 

Leaky Rear

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Aug 31, 2017
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upon trying to remove the raw water pump . trouble getting to one screw. There is a huge gob of a very black thick grease around the raw water pump where it screws on. Wonder what the grease came from?
 

Leaky Rear

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Aug 31, 2017
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Making progress, in a sense . Heres the worn out raw water pump impeller.
And the spline it sits on. What do yo all think going on with the spring and seal , that appears broken.

To remove raw water pump there was huge gobs of thick black grease covering the area where the bracket that bolts to the block comes out and in front of the raw water pump.
 

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Leaky Rear

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the boat dealer said the spline assembly in first pic comes off with 8mm allens.
He said cbring in can rebuild cheaper than new. Maybe that is where the mystery grease came from? :confused:
 

Lou C

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Can't help on the Volvo pump as all I've had is the OMC Cobra but here's a pic of the bypass....
The OMC Cobra and the Volvo SX models used the same exact thermostat housing and thermostat for a number of years, yours is the same as the OMC part.
 

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