1980 mercury 70 no tattle tale

YN2(SS)

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I am bringing this motor to life and have rebuilt the water pump and replaced the impeller. When I plAce the muff on the lower unit, no water comes out the tattle tale. With city water @ 40 psi, shud it? PO stated he had run it in slot of silt and mud. If the power head passages are clogged, do I jus need to remove and clean the head and exhaust cover and replace gaskets? What path does the water take when it enters the bottom of the powerhead to leaving the tattle tale?
 

MacDaddy21

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Re: 1980 mercury 70 no tattle tale

Are you saying you hook it up to muffs, then start the motor and no water exits the tell-tale? Or are you saying with the muffs on, and the motor not running, no water is coming out?
 
M

Maxz695

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Re: 1980 mercury 70 no tattle tale

Good question to the question. The engine must be running in order to pump the water. Restrictions can be in the Block base plate, exhaust port cover thermostat and the water jackets. Some fuel pumps have water that run through them as well where the water hose comes from the exhaust port to the tell tale that can be totally clogged
 

MacDaddy21

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Re: 1980 mercury 70 no tattle tale

Maxz695, you have some of the best pics. I guess I'd have some like that too if I had ever torn mine down that far, but I didn't have to.
 

YN2(SS)

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Re: 1980 mercury 70 no tattle tale

That's for the input guys. I have not got it "running" yet, jus muffs on and water applied and turning the motor over to try to get it started. That's a fuel issue that will be resolved shortly. I had forgotten about the base plate. I had a 1980 Merc 40 that wud pee a little with water on, so I guess I was surprised to not see it. So the game plan will be to get it running , and if it doesn't pee, the I'll get gaskets to do the base plate and exhaust cover and head and prepare to deal with the broken bolts.
 

YN2(SS)

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Re: 1980 mercury 70 no tattle tale

Well,
We attempted to start the motor yesterday, and got it running for short periods of time (8-10 second bursts). I'll deal with those issues later. We still didnt have any water coming out of the pee hole, so we stopped attempting to run the motor and decided to chase this down. So we pulled the cylinder head cover (not really a head). It was a little dirty inside, but not bad. So, I pulled the exhaust cover (both pieces), again a little dirty, but not bad. So we lifted the powerhead and removed the base plate, and found that water had been lifted into the base plate, and the base plate was wet above the copper tube, but the base plate had not even filled with water and pushed the water uphill. So, either the water pump is not working, or we didnt have it running long enough, or the new impeller isnt working properly. When I had worked on the lower unit before, I replaced the impeller and inspected the water pump casing and it looked good, but I'm gonna pull it again (need to anyway to mount the powerhead) and check everything out there.
 

ufm82

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Re: 1980 mercury 70 no tattle tale

If that engine has a thermostat you'll get no flow until the stat opens up. And by the time you've pulled it apart the water will have run out of the engine. You'll need to get the engine running long enough for it to warm up before you see a tell-tale.
 

MacDaddy21

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Re: 1980 mercury 70 no tattle tale

As soon as the motor fires, water should be exiting the tell tale. When I get out to the lake and haven't started my motor in a week or two, I'll have to crank it once or twice with the choke and even when it cranks, water will dribble out the tell tale, and as soon as it fires, its a steady stream. The pressure of the stream should increase at WOT. If you don't see water within 5 seconds, shut it off.
 

ufm82

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Re: 1980 mercury 70 no tattle tale

Is that for this specific engine? Mine doesn't pee until the t-stats open up. My tell tale is after the t-stat housing fittings. It's a Merc.
 

MacDaddy21

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Re: 1980 mercury 70 no tattle tale

No it isn't for this specific engine, so that may make enough difference, but on my merc, the water travels through the t-stat before exiting the tattle tale. mine is a 1979 40hp with the t-stat housing off of my 1980 40hp parts motor.
 

YN2(SS)

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Re: 1980 mercury 70 no tattle tale

I'm glad someone has brought up the ? Of the thermostat. Where is it located on his motor, if it has one? I removed the exhaust housing cover on the port side and saw a spot that I thought it might go into. Jus nothing was there. If u run the o/b without a thermostat, what are the results? I've heard it will warm up quicker but if u run idle for long periods of time the plugs will foul. Anyway, my motor is a 1980 Merc 70 see 5651730
 

YN2(SS)

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Re: 1980 mercury 70 no tattle tale

Btw, when I removed all the covers, there was no water anywhere in the engine. Should I "prime" it from the top by pouring water into the cooling system? It jus seems it wud take a lot of pumping to get all the cavities filled up and have water finally coming out. Im sure part of why it's hard getting it started is cuz there is no water to get the fuel pump running.
 

Sunfish12

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Re: 1980 mercury 70 no tattle tale

You don't need to prime it the water will pump through when it starts. Your problem could be as simple as snaking the peehole with a piece of weedeater string. But while it is apart you can spray water into the engine ports and see if the water comes out. There shouldn't be water in the engine when you took it apart. The water drains down as soon as the engine is shut off and in your case when the garden hose is turned off.
 

pmcintyre

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Re: 1980 mercury 70 no tattle tale

WOW! This is a very informative forum, more so than most. And really nice people that are not rude to noobs. That said I am having the same prob with my 1970-71 merc 650, when I start it nothing from the tattle tell holes at all, weather submerged up to the pump or with muffs. there is a small hole in the head cover with a threaded plug in it, when I remove it (plug) water starts to weep at first then after it warms up (about 1-2min.) there,s a very strong spray coming from it, and with the muffs on there is a tinny amount of water out the exhaust , could the tattle tell holes (small set of rectangular holes at rear power-head base) be plugged with a mud dobber nest or something? checked impeller & housing for excessive wear & they're good, also would it have a thermostat? thanks for any info.
 

Gibbles

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Re: 1980 mercury 70 no tattle tale

You don't need to prime it the water will pump through when it starts. Your problem could be as simple as snaking the peehole with a piece of weedeater string. But while it is apart you can spray water into the engine ports and see if the water comes out. There shouldn't be water in the engine when you took it apart. The water drains down as soon as the engine is shut off and in your case when the garden hose is turned off.

This ^

I recently brought a 1975 merc 65hp back to life and installed a new waterpump, had the same issue.

Engine felt cool to the touch, but I had a very weak tattle tale.

So I put the engine in a tank and ran it long enough to warm up thinking it was the thermostat, still nothing.

Then I got the bright idea to stick a string from my weed eater up the lines while it was running (idea from this forum), and a good stream of water came out. :)
 

Gibbles

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Re: 1980 mercury 70 no tattle tale

WOW! This is a very informative forum, more so than most. And really nice people that are not rude to noobs. That said I am having the same prob with my 1970-71 merc 650, when I start it nothing from the tattle tell holes at all, weather submerged up to the pump or with muffs. there is a small hole in the head cover with a threaded plug in it, when I remove it (plug) water starts to weep at first then after it warms up (about 1-2min.) there,s a very strong spray coming from it, and with the muffs on there is a tinny amount of water out the exhaust , could the tattle tell holes (small set of rectangular holes at rear power-head base) be plugged with a mud dobber nest or something? checked impeller & housing for excessive wear & they're good, also would it have a thermostat? thanks for any info.

The manual for my 1975 650 (3 cyl model) shows a thermostat, but I seem to get a tattle tale anyways...

This could be due to an issue with the thermostat, or maybe someone took it out at one point...

For your engine I would start by testing how warm it gets by holding your hand on the engine heads, if really hot you may have an issue.

If you put water on it, it should not sizzle away.

Start by checking the water tube, make sure its in there correctly and not obstructed.
maybe even try and force some water or air up the tube it self.

and on my 650 I have two hoses in the tattle tale location, one is for the tattle tale, and the other is the drain line for the carb/airbox

And I put a good 3-4ft of weed eater line up my tattle tale hose until it started spraying.
 

pmcintyre

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Re: 1980 mercury 70 no tattle tale

OK I cant believe the weed eater line thing worked! I kept telling myself that was crazy. then I found the tiny tattle tell hose & it was clogged, so I cut a piece o line off my weed eater & shoved it up in there then started it & I'll b d*mned it worked! U guy's r great!
 

Sunfish12

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Re: 1980 mercury 70 no tattle tale

Pmcintyre, you were one of the lucky ones with a simple fix.
 

YN2(SS)

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I'm not one to bump an old thread, but since it's mine... I still am having this problem with my motor. Yes, I started working on this in 2009, and then the project got sidelined. And life got in the way. Last summer, it was in 2 shops bringing it back to life again dealing with ignition issues. But, with it running now, it still won't tattle tale at idle. It also won't push any water out of the brass nipple for the tubing that goes to the water pressure gauge. But once I put it in gear and raise the idle, it will. and the water is not very hot. This happens on muffs but less so on the lake. Is there some deficiency in my cooling system? I have had the cylinder head cover removed and it was clean. Impeller is a year old with less than 2 hours of operation on it (mostly idling). I've lifted the power head and replaced the gasket. Blown compressed air backwards through everything I can find. What am I missing?
 
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