1969 Evinrude 40hp Lower Unit

[jimmbo]

Wow! You're learning just about everything you could ever learn about that engine design. Probably more than you wanted to know. I see you pulled the exhaust tube out. Yes clean all the carbon, it might reveal a clogged up passage. With the powerhead off you should be able to trace the path the water would take to the idle relief, probably find more sand. I hope in the end you have yourself a fine running engine

edit: in your picture, is there an opening where I drew the arrow. It looks like light is getting in there from the back

 

[Chrisravosa36]

edit: in your picture, is there an opening where I drew the arrow. It looks like light is getting in there from the back

This is the outer plug core, took it out to remove it, there was some sand in debris in it. None of the holes in the the exasut housing are blocked. Im trying to figure out how the exsaust releif works, how does water get into it? Im getting a new o-ring for it and gasket, but not sure what else to do......Im positive its pumping through the powerhead, not sure how it goes from there.

 

[jimmbo]

That core plug is directly above the exhaust relief? Looking at the picture of the powerhead, it looks like the cylinder head was replaced at one point. Have you had the head off?

 

[Chrisravosa36]

That core plug is directly above the exhaust relief? Looking at the picture of the powerhead, it looks like the cylinder head was replaced at one point. Have you had the head off?

yes, I have had the head off, replaced the head gasket and cleaned up the cylinders. Why would this matter?

 

[jimmbo]

Just trying to add up what you've done.

Normally how the exhaust relief works, Exhaust exits thru the 5 little holes at idle, as engine speed increases more water flows across the holes, effectively blocking them.

 

[Chrisravosa36]

Just trying to add up what you've done.

Normally how the exhaust relief works, Exhaust exits thru the 5 little holes at idle, as engine speed increases more water flows across the holes, effectively blocking them.

Are you talking about those two little holes? Should their be more of them? I only have two on this motor.

 

[Chrisravosa36]

This is the picture of the exsaust housing I have.

 

[jimmbo]

I was referring to several holes that F_R mentioned that reside behind the plug above the exhaust relief(where the big rubber hose goes) The two you show in the latest picture are the ones that either let the exhaust out to get to the idle relief, or to allow water into the exhaust, or allows any water in there to drain when motor is vertical, maybe all of the above

 

[Chrisravosa36]

I was referring to several holes that F_R mentioned that reside behind the plug above the exhaust relief(where the big rubber hose goes) The two you show in the latest picture are the ones that either let the exhaust out to get to the idle relief, or to allow water into the exhaust, or allows any water in there to drain when motor is vertical, maybe all of the above

Il take alot of pictures, my not sure what you are talking about

 

[Chrisravosa36]

I was referring to several holes that F_R mentioned that reside behind the plug above the exhaust relief(where the big rubber hose goes) The two you show in the latest picture are the ones that either let the exhaust out to get to the idle relief, or to allow water into the exhaust, or allows any water in there to drain when motor is vertical, maybe all of the above

I have found 4 holes, 2 on one side, one on the other of the exhaust relief. I also found 2 odd shaped holes on the bottom of the exhaust housing I arrowed them in a pic, normal?! Cleaned up alot of the carbon and shined up the gasket surfaces, new one is on the way.


(COULDNT ARROW THEM SO LOOK DOWN THE EXHAUST AND YOU WILL SEE THEM ON THE TOP)

 

[jimmbo]

In the top picture. the arrow with the circle, are there any holes there? and the arrow to the right in the picture, is that the idle relief hole?
In the bottom pic I circled what at first looked like a passage, but the lighting is poor, it might just be a taper on the wall

Careful with the bare feet, those hammers can hurt

 

[Chrisravosa36]

In the top picture. the arrow with the circle, are there any holes there? and the arrow to the right in the picture, is that the idle relief hole?
In the bottom pic I circled what at first looked like a passage, but the lighting is poor, it might just be a taper on the wall

Careful with the bare feet, those hammers can hurt

There are no holes their, just two in the back, one for the exhaust relief and one that goes to that plug core.

 

[Chrisravosa36]

I just looked again, one of the holes is a rectangle shape (the plug core one) and it is smaller, and the other is a circle, and that is the exhaust relief. At this point, I have all the new gaskets on the way for the exhaust, I'm hoping this problem was just a bad gasket, or because of the carbon....

Mod EDIT: Please remember the host of this free forum is an online retailer

Because everything matches on the diagram and is clean.....At least I will know now that I can run it without smoke in the cowl :thumb::thumb: Also, thank you so much for helpig me everybody! I wouldnt know what to do with your help!! :hail::hail::hail::hail:

 

[jimmbo]

Also, thank you so much for helpig me everybody! I wouldnt know what to do with your help.

Well we, well some of us, did encourage you to buy this engine(praising its MUCH better design) instead of the other Frankenrude/Johnstone you initially posted about:embarassed:

 

[Chrisravosa36]

Well we, well some of us, did encourage you to buy this engine(praising its MUCH better design) instead of the other Frankenrude/Johnstone you initially posted about:embarassed:

Thats why I thank you! Ive learned much more than I would have with that other engine! Besides, someone would have gone through these problems with the engine!! Glad to be putting an old engine back in service :joyous: Im hoping the water pump/exhaust relief will work after this!!!

 

[jimmbo]

While you got the powerhead off, you have access to where some of the water passages are, I would also take the exhaust cover off again and look for more sand/mud. It's apart right now, beats taking it apart again later. There is one other place where sand could be packed in, behind the water jacket cover on the cylinder head

 

[Chrisravosa36]

While you got the powerhead off, you have access to where some of the water passages are, I would also take the exhaust cover off again and look for more sand/mud. It's apart right now, beats taking it apart again later. There is one other place where sand could be packed in, behind the water jacket cover on the cylinder head

Ive tackled both of those spots, the head jacket when I replaced the gasket and the exhaust more recentally.

 

[Chrisravosa36]

So guys, where is the pressure plug, or whatever they call that on this motor? On my 50hp it was a little red plug with a spring attached. I looked all over with no luck! So far I got the new gaskets on the exsaust housing and am about to place the powerhead on.

 

[jimmbo]

The thermostat is sitting on/in it. The thermostat fits into a plastic liner, at the bottom the liner there is a spring loaded valve. that's the pressure valve

 

[Chrisravosa36]

I dont belive I have that in my motor, is that a problem?