1961 Mercury 700 FGS Tell-Tale location?

zebraman1978

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Apr 8, 2010
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i'm looking for where the tell-tale should be to verify water flow. there is no peeing now, so i want to be sure i know where it is to clean it out if clogged. previous owner said it had a new water pump but all the crap i went through to get this running makes me wonder... It starts and runs fine now. idles good and there is some water kind of spitting out of the exhaust. haven't been able to locate a manual for this year.

i've read here on iboats that one should be able to leave ones hand on the side of the engine and feel warm but not hot. does this mean that i should be able to feel any part of the motor and it not be hot?

thanks
 

ktonkel

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Jun 30, 2010
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Re: 1961 Mercury 700 FGS Tell-Tale location?

The outlet should be on top of the powerhead under the cowl. You'll have to take the cowl off to get to it. On mine it looks like right angle adapter for 1/8" NPT to a compression fitting. When I got the boat from Dad, the tube had a kink in it and it would only drip. I disconnected the compression fitting and it pumped water 15' or so across the yard. Replaced the tube and it's fine. Well, the water pump is fine.. I'm having another issue with the motor now. >.<
 

zebraman1978

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Apr 8, 2010
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Re: 1961 Mercury 700 FGS Tell-Tale location?

thanks for the info. can't remember seeing that but wasn't looking specifically for it either. i'll see what i can find. would you be able to take a picture and upload it?
 

ktonkel

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Re: 1961 Mercury 700 FGS Tell-Tale location?

edit: link didn't seem to work.. I'll try again later
 

emckelvy

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Jan 16, 2004
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2,506
Re: 1961 Mercury 700 FGS Tell-Tale location?

Merc 700-6 doesn't have a water tube. It has a passage from the exhaust manifold thru the bottom of the block, to a hole drilled into the lower cowl.

If you look up underneath the lower cowling on the Port side of the motor, towards the rear portion of the exhaust manifold cover, you should see the hole. It's drilled at an angle, to fire out the Port side.

If you can't clear this hole with wire or air, the passages are probably plugged up inside the exhaust manifold cover. It's quite convoluted and to clear any blockage up there would require you to pull the powerhead then manifold cover and clean out all passages. Can you say broken bolts? I knew you could!

Failing the original telltale, you could retrofit a telltale by tapping into the cyl block cover (the one over the spark plugs); drilling/tapping a 1/8"-NPT hole at the top of the block for a fitting, or installing a fitting into an existing hole. Some blocks did have a stainless pipe plug at the top Port side, if you're lucky enough to have this all you have to do is get the plug out. Heat and an impact driver should do it.

If you decide to drill, it'd be better to do so with the back cover removed, so you can capture any shavings and more importantly, not drill into something important!

You could retrofit a telltale fitting from any number of motors, or make your one. It'll need a small hole so as to get proper spray.

Having the telltale fitting connection at the top of the block does have an advantage in that it ensures the block is fully vented of air, and eliminates the possibility of a 'steam pocket' forming inside the main chamber.

HTH.........ed
 

zebraman1978

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Apr 8, 2010
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Re: 1961 Mercury 700 FGS Tell-Tale location?

glad to hear from you again emckelvy!

based on your description then, it makes sense that there is water spitting out of the exhaust? assume flow is good? if so, how warm should the motor get and be safe from overheating?

still curious to see ur pics if you get a chance ktonkel.
 

emckelvy

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Jan 16, 2004
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2,506
Re: 1961 Mercury 700 FGS Tell-Tale location?

Water spitting out the exhaust relief ports (I assume that's what you mean) or warmer water spilling from the center of the prop are good indications of water flow thru the powerhead.

Feel the exhaust manifold cover, it should be cold when you're running on a flusher. There's no exhaust backpressure and no load on the engine, so it's never gonna heat up as long as nice, cool water is flowing thru the powerhead.

After a hard run in the water, the exhaust manifold cover may be lukewarm or perhaps even a bit warmer than that (depending on temp of the body of water you're running in), but if it's ever too hot to lay your hands on it comfortably, it's WAY too hot.

This motor doesn't have a thermostat and so should never get that warm unless there's a water circulation problem...........ed
 

ktonkel

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Jun 30, 2010
Messages
9
Re: 1961 Mercury 700 FGS Tell-Tale location?

Gonna try this again:

IMG_0245.jpg

IMG_0247.jpg


This is how it is on my motor. I don't remember if he did it that way or if it was that way when he bought it. I'm not sure if he'd remember, hehe. :D
 
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