thermostat housing

[splitshot]

I just finished the rebuild of a 1978 140 evinrude went to start and it fired right up but then i noticed the water....it was getting dark on me so really couldnt tell exactly where it was comming from i am suspicious of the thermostat housing though...so i have been researching on here some and was wondering what is the best way to pull the thermostat housing on these motors ?? is it easy as unbolting the lower pan and pulling it down some ?? any help is greatly appreciated i did put new thermostats in during rebuild, so if it is this i guess i got something wrong i'll let yall know what i find thanks Jason

 

[AguaSki]

Re: thermostat housing

I have a 1978 Johnson 140 hp (basically the same motor as you), and I did the thermostat and impeller last weekend. I did not remove the lower pan, but I probably should have. Instead I removed the piece just below the pan. With that piece removed I could get a wrench on the two outside bolts. The center bolt was tricky, but I improvised by putting a socket on the bolt. On the socket I inserted a piece 1/4 carbide that stuck out just enough for me to put an adjustable wrench on it from above for twisting. The bigger trick was getting everything put back together. My Dad was assisting me, so we had 4 hands, and we needed all 4. We found that we could get all the pieces in place, and then used a large flat blade screw driver as a lever from beneath to hold everything in place until we got the bolts threaded. This actually took several tries, but eventually we got it put back together.

FYI - When I started my motor I had no pee stream. Turns out the problem was with my impeller job and not the thermostat. I found out my key fell out of place as I slid the impeller down the shaft. Due to time commitments I was not able to get back to the motor until yesterday. All is good now.

 

[ezeke]

Re: thermostat housing

Where are you seeing the dark water? The exhaust and water are mixing as they exit the lower unit, so that would be normal at that point.

 

[emdsapmgr]

Re: thermostat housing

You need to decide where the water is coming from. Could be the powerhead base gasket, exhaust cover gasket, head gasket, either of the two hoses from the heads to the thermostat housing, or the thermostat housing itself. None of these should leak. Save yourself some time and find out where the leak is first. That thermo housing is a bear to get off, esp on the bubble back model-like yours. Did you reconnect the exhaust cover telltale hose to the nipple in the lower cowling?

 

[splitshot]

Re: thermostat housing

No dark water i meant the sun was setting fast ("getting dark on me")....i know i am going to find the source in the morning i was just wondering the best way so i could get started if that is it...thanks for the advise

 

[splitshot]

Re: thermostat housing

well i figured it out, it was the bottom of the bubble back exhaust housing put silicone on the gasket this time and worked like a charm...now i have one other problem....the bottom of the starboard head has a slow drip of water (one drop every 10 seconds) from what i can see i believe its in between the head and block i have torqued it down properly and the head gasket is turned the right way....anybody ever had this problem before ??

 

[emdsapmgr]

Re: thermostat housing

I've never had a head gasket leak. Most of the new ones are coated and you do not need to use OMC gasket sealer on them. The original service manual says to use the OMC gasket sealer, but that was probably on the head gaskets available at that time. It will not hurt to use gasket sealer, esp if you have a leak issue. You should retorque both heads after the engine goes through the first heating/cooling cycle. That might take care of it. Did you check the head to insure that it was perfectly flat before you reassembled and torqued? Sometimes they will warp if seriously overheated.

 

[splitshot]

Re: thermostat housing

i checked with a straight edge looked good...might have to try the sealer if it dont stop when i retorque..is it a special sealer or just rtv silicone ?? thanks