1969 Evinrude 40hp Lower Unit

[F_R]

The rest of the story: When the 'stat is closed, the water returns to the water pump through the second tube. Then it returns to the powerhead again. This continues till it is warm enough to open the 'stat. When open, water is discharged and replaced with cold lake water. This is not an either-or situation. The 'stat is constantly monitoring the temp and opening or closing as necessary to maintain proper temp. In cold water and idle speed, it may never get warm enough to open the 'stat.

This is exactly how the cooling system works in a car, except the car uses a radiator instead of a lake to supply cool water. And of course it doesn't spew any water out along the road (hopefully).

 

[Chrisravosa36]

The rest of the story: When the 'stat is closed, the water returns to the water pump through the second tube. Then it returns to the powerhead again. This continues till it is warm enough to open the 'stat. When open, water is discharged and replaced with cold lake water. This is not an either-or situation. The 'stat is constantly monitoring the temp and opening or closing as necessary to maintain proper temp. In cold water and idle speed, it may never get warm enough to open the 'stat.

This is exactly how the cooling system works in a car, except the car uses a radiator instead of a lake to supply cool water. And of course it doesn't spew any water out along the road (hopefully).

Ok, so should I try it with the stat out?! To see if water will even flow through it?

 

[Chrisravosa36]

Tried with the stat out, no water just smoke coming out of exhaust relief. I took off the side mount exsaust on the powerhead, found about a spoonfull of sand....I dont think this is it, but I cleaned it up and gotta get some new gaskets now. I honestly have no clue what this could be... One thing I though I should have done is flush the motor....Didnt do that but could try it tomm?

 

[oldboat1]

imo, flushing may be your solution. Sounds like you might have found the remnants of a mud dauber nest.

 

[Chrisravosa36]

imo, flushing may be your solution. Sounds like you might have found the remnants of a mud dauber nest.

*sigh* well Il do it tomm I guess....Which tube do I put the hose up to? The one that is attatched to the pump housing right?

 

[oldboat1]

Think I would do them both -- get a back flush going too.

 

[Chrisravosa36]

Think I would do them both -- get a back flush going too.

Back flush? Should I use some drano in the hose? Or something along those lines to really break up anything in the way? I have a high presure nozzle I will probally stick up to and it run it till I get some damn water out the back...... ALSO just found out this is a thermostat from another motor, a 10hp.....I ordered another proper one.

 

[oldboat1]

Well, if the t.stat is out, I would flush down from there too -- want to be sure the t.stat housing is clear, bypass or whatever. Moderate pressure. Simple fresh water flush -- good for silt or salt (or wasp nests).

 

[Chrisravosa36]

Well, if the t.stat is out, I would flush down from there too -- want to be sure the t.stat housing is clear, bypass or whatever. Moderate pressure. Simple fresh water flush -- good for silt or salt (or wasp nests).

I did the top of the thermostat housing with no luck.....When I sprayed down there I just go water spraying out of the bottom of the lower unit (exsaust pipe) Just to be clear, where does the water go? what is the path of it when it enters the motor? ANd how long should I flush for?

 

[Chrisravosa36]

Also, the tempture switch in broken, I need to get a new one. Where is the welsh plug located? Right now the temp switch is just the rubber part. Im not sure if this has anything to do with it.

 

[racerone]

?-----But a 10 hp Johnson uses the same thermostat as the 40 hp.---Along with many other models.

 

[Chrisravosa36]

?-----But a 10 hp Johnson uses the same thermostat as the 40 hp.---Along with many other models.

Oh, ok...It was a bit damaged anyways, so Il just use the new one that is coming. Im thinking of taking out part #23 (Plug Core) It is the Metal plug that is at the bottom of the thermostat housing, it is facing the outside of the motor on the bottom.

 

[racerone]

And why do you think you should remove that core plug?

 

[Chrisravosa36]

And why do you think you should remove that core plug?

POSSIBLY...Could there be something stuck down there?! Im not going to do it unless it is advised. When I get home il drop the l.u and flush it. Should I exspect water coming out of the exsaust relief? Is there solution that would help? Such as drano, soap or any solvents?!

 

[AlTn]

the old formulation of drano used aluminum chips to create heat in the presence of water < a lot of heat > we used to use it to eat holes in the old pie pans that frozen pies came in < kids will entertain themselves >... so, I'd try it on some aluminum first before using it as any type of cleaning agent

 

[Chrisravosa36]

the old formulation of drano used aluminum chips to create heat in the presence of water < a lot of heat > we used to use it to eat holes in the old pie pans that frozen pies came in < kids will entertain themselves >... so, I'd try it on some aluminum first before using it as any type of cleaning agent

Il just use water and see what that does first, il play it safe...

 

[Chrisravosa36]

Did the flush for about 5 mins, not water out of the exhaust relief.... The only thing I can think of to do now is to pull the head and inspect the powerhead to midsection gasket and assembly. Any thoughts? When I squirted it up the tube, it came down the other tube.......

 

[Chrisravosa36]

And why do you think you should remove that core plug?

Also removed the plug core and found somemore san in there, it was really stuck but I freed it, put a new one in and no luck... The water is cooling the motor, but it just wont go to the exsaust relif....... Im so confused!!

 

[Chrisravosa36]

^ anything

 

[Chrisravosa36]

Ok, so ive made some progress. I disconnected all the stuff to pull the head, pulled it and ordered a new gasket, all in shape. pulled the exhaust housing relief thing and everything looked normal...Nothing out of place...I am going to get a new exsaust gasket and O Ring Seal. At least I have resolved the smoke problem. I had to get a special wrench to get those two front bolts. What should I do now? clean all the carbon up? Not sure what could be wroung with the water flow....