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1982 Evinrude 15 hp

D

DrCoxie

Contributing Member
Hello, it's me again, I have now completed the restoration of my engine and it runs good in all aspects but one, cooling. Before the restoration I had water coming out the telltale but that's it, the water was just warm (I also ran without a thermostat).
After restoration I now have a thermostat and it's very clear when it opens because when it does the telltale goes from pissing like a racehorse to something like a child playing water fountain while the water is very hot and eventually there is also steam coming out so clearly the motor is overheating (water on top of the block starts boiling off right away).
It seems almost like the motor is overheating more now with the thermostat and cleaned water passages than it was before. Pretty sad about that as everything else seems to be running just great (its my first complete engine restoration) and I'm wondering if anyone here can give me a ray of hope in some way? Could I run something through the engine to clear the passages further or are these signs of having put something together wrong?
 
What does " complete restoration " mean here.------Paint or mechanical work.-----The water from the tell tale should be cool as it does not circulate through the engine block.-----Sounds like you have a blockage somewhere.
 
Mechanical restoration, literally the only thing I didn't do was split the block but i inspected the rings, cylinder walls and pistons which looked in decent condition (cold compression without backpressure from water was at 100 psi.
But when the thermostat opens water circulates through the water jackets to cool the engine and then it comes out of the telltale, right?
When the engine is cool the stream is really good but as the engine gets warm it lessens, that's the thermostat opening right? or am i missunderstanding something?


edit: any ideas on how to deal with such a blockage?
 
...then how does the cooling water that circulates the block exit the engine?

and what does the thermostat really do then?
 
Are you test running in a bucket ?----If yes is the water lever 6" above the pump?-----Just once more.----Accept the fact that the water from the tell tale does NOT go through the block or thermostat.
 
The water is just above the pump but not 6'', that is something I'm going to have to digest... how come the water stops flowing out of the telltale when the engine heats up and what is the steam and why is the telltale water so hot? so many questions xD
 
DrCoxie said:
The water is just above the pump but not 6'', that is something I'm going to have to digest... how come the water stops flowing out of the telltale when the engine heats up and what is the steam and why is the telltale water so hot? so many questions xD
Click to expand...

You, sir, are a genius. Just filled the bucket to the rim with water and now it's not overheating one bit, perfect temperature, pee stream still isn't the strongest when it gets warm but it's no longer oveheating, it's like its a different engine, runs fantastic, now I can chuck in the new pluggs I've been holding on to for months and give the old girl the love she deserves. Amazing how something so simple can have such a huge effect (I did commit the sin of running the engine in a dirty old barrel and now the telltale kinda stopped, I think I have some **** in the system now but ill flush that out with some compressed air (I know I'm an idiot).

Anyway, thanks a lot for the help, I'm so glad the engine works;DDDDD
 
A question you kept asking that went unanswered....... The very first portion of the engine that the incoming water is directed to is the exhaust baffle section, which happens to be right where the water telltale outlet elbow is located. As such, water would flow out the telltale even if the entire powerhead water passageway was clogged solid.

The thermostat functions as you suspect it does excepting that some water does get by it via a spring loaded water bypass valve setup (usually)... and when the thermostat opens (at around 143 or so degrees), the telltale pressure would naturally drop somewhat as the back pressure of water would now be flowing thru the block.
 
joereeves said:
A question you kept asking that went unanswered....... The very first portion of the engine that the incoming water is directed to is the exhaust baffle section, which happens to be right where the water telltale outlet elbow is located. As such, water would flow out the telltale even if the entire powerhead water passageway was clogged solid.

The thermostat functions as you suspect it does excepting that some water does get by it via a spring loaded water bypass valve setup (usually)... and when the thermostat opens (at around 143 or so degrees), the telltale pressure would naturally drop somewhat as the back pressure of water would now be flowing thru the block.
Click to expand...

Thanks a lot, that makes it clear, so ultimately the water that cools the block does come out the telltale, and I'm guessing that the pressure drop wouldn't be as noticable in the telltale when you ran the engine at WOT since the impeller would spit out a lot more pressure. Good to know, now I just need to clear out the crap I just blew into my engine via the dirty ass water I used ^^
 
The water that comes out the tell tale does NOT go through the engine block.-----It is merely an indication that the impeller is pumping.------Does NOT tell you that the motor is cooling properly.
 
racerone said:
The water that comes out the tell tale does NOT go through the engine block.-----It is merely an indication that the impeller is pumping.------Does NOT tell you that the motor is cooling properly.
Click to expand...

Ok, so what you're saying is that the reason the telltale diminishes is because the backpressure from the water that gets heated in the engines cooling jackets pushes out of the telltale when in fact it should come out somewhere else? they're two seperate systems and the steam out of the peehole suggest a blockage in the water jacket passages which prevents the cooling water to exit next to the exhaust, that's what the second smaller tube is for then right?
But since it's now cooling properly and what solved it was to lower the engine deeper into water resulting in better impeller function means that the water pressure pushing up from the impeller has become greast enough that the cooling water is now pushed out the proper passage rather than pushing back. But the telltale still diminishes because there will always be some backpressure whatever you do, at least with this system.
Does that sound about right?
 
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