How does water enter cowling to the tattle tale on '67 Merc 39?

I got a '67 Mercury 39 (3.9 HP) with a jon boat I purchased last fall. The boat and trailer were worth what I gave for it so the motor was a 'freebee', and the guy who had it before me never used it.

I put it in a trash can of water and that baby started right up, however I noticed there was no water coming out anywhere and just a bunch of smoke - so I shut it off immediately.

I pulled the lower end and found the impeller to be in pieces (I found and removed all I'm fairly certain). I ordered a new impeller, installed it, put it back together and still no water.

The lower unit was pulled again and the copper water pipe was checked for obstructions - none found. Ran fine wire into the tattle tale hole and when it pulled out it was covered in dark grease like material.

We then pulled the powerhead and the cover over the W shaped maze which drains to the tattle tale. This was full of all kinds of that dark grease. We cleaned it out and all the canals in the powerhead and bolted it back on. Fired it up and it would surely spray water right? Wrong.

There was water spraying out of the small hole next to the bolt underneath on the side, but what feels like only a fine mist and warm air coming out of the back tattle tale. We even pulled the fresh water flush plug and water was pouring out of it - so the pump is working fine.

I'm not sure what to even try anymore. When looking at it with the powerhead off, we couldn't even figure out how the water would get into that area where the tattle tale is located? There is no hose which leads to it or area that would drain into it? How does that work?

Please help! My grandpa and I have spent hours on this and he is giving up. Thanks!

Re: How does water enter cowling to the tattle tale on '67 Merc 39?

I'm not totally sure with this, but I think a possibility is that the small hole you mention has water coming out of it is the tattletale. The hole in the back may be an exhaust relief.
I've not worked on that model......
60's Mercury outboard boat motor running - YouTube
I looked up a video---it appears the back hole is an exhaust relief, but should have a spray of water coming out of it as well.
Wish I could be more helpful....
JBJ

Re: How does water enter cowling to the tattle tale on '67 Merc 39?

^^^^^I have a Merc 39 and agree with jbjennings above^^^^^

What he said is spot on. The "back tattle tale" as you mention, as has been said by jb, is simply an exhaust relief so warm air and and fine water mist is perfectly normal.....

Now the fine hole next to where the powerhead bolt/nut is located is the actual tattle tale for this engine. As long as you have a steady stream comming for there, all is fine. There isn't much water pressure that goes through there at all and was only put the there as an indicator for the owner that water is circulating..........
90% of the engine coolant water goes straight through the exhaust leg and you'll never actually see it because it exists via the prop.....

If it doubt, as long as the power head is cool to touch and never gets any hotter than "luke warm" you'll be fine. I like to place my hand on the exhaust cover as this again if all is well, should never get hot to touch and will stay nice and cool.

Hope this helps.

Re: How does water enter cowling to the tattle tale on '67 Merc 39?

jbjennings said:

I'm not totally sure with this, but I think a possibility is that the small hole you mention has water coming out of it is the tattletale. The hole in the back may be an exhaust relief.
I've not worked on that model......
60's Mercury outboard boat motor running - YouTube
I looked up a video---it appears the back hole is an exhaust relief, but should have a spray of water coming out of it as well.
Wish I could be more helpful....
JBJ

Click to expand...

That's the exact video that I was using for reference. The best that we got was a short spurt of water coming out of the back hole when I think condensation got built up... where in the video it looks to have a generous flow.

Re: How does water enter cowling to the tattle tale on '67 Merc 39?

mercuk said:

^^^^^I have a Merc 39 and agree with jbjennings above^^^^^

What he said is spot on. The "back tattle tale" as you mention, as has been said by jb, is simply an exhaust relief so warm air and and fine water mist is perfectly normal.....

Now the fine hole next to where the powerhead bolt/nut is located is the actual tattle tale for this engine. As long as you have a steady stream comming for there, all is fine. There isn't much water pressure that goes through there at all and was only put the there as an indicator for the owner that water is circulating..........
90% of the engine coolant water goes straight through the exhaust leg and you'll never actually see it because it exists via the prop.....

If it doubt, as long as the power head is cool to touch and never gets any hotter than "luke warm" you'll be fine. I like to place my hand on the exhaust cover as this again if all is well, should never get hot to touch and will stay nice and cool.

Hope this helps.

Click to expand...

If yours doesn't shoot water out of the back hole, and you haven't had any issues, I won't worry about it anymore then. Boy sounds like we wasted a lot of time trying to figure out how water would flow out of there...