1971 mercury 800 telltale problem

[breakingaway1322]

I'm having problems with the telltale on my 71 merc 800 serno 3147233. Water just dribbles out at idle. I've replaced the impeller and pump housing to no avail. Not having any cooling problems as the exhaust coverplate and cylinders aren't getting hot but for some reason the telltale isn't spraying like it should. Any help would be greatly appreciated.

 

[Moody Blue]

Re: 1971 mercury 800 telltale problem

Is the motor new to you?

Is this a new problem?

Is the motor on muffs with a garden hose or IN the water?

Have you cleaned out the telltale line? A piece of weed trimmer line works well. Often, insects like to crawl up in there and plug things up.

 

[breakingaway1322]

Re: 1971 mercury 800 telltale problem

It's a project motor that I started working on about two month's ago. I'm not sure the last time it's actually ran as I've had it for about four years sitting in my back yard without a lower unit on it. I was running it with muffs. I also tried circulating water up through the copper tube with a hose and the same result water pouring down the side of the exhaust tube but just dribbling out the telltale. I also disconnected the telltale line and ran safety wire through it with no obstruction to it.

 

[breakingaway1322]

Re: 1971 mercury 800 telltale problem

I've been reading through a few other threads on the same problem and heard talk of moving the telltale to a fitting on the cylinder head. My motor has the fitting but it's located between the #2 and #3 cylinder not at the top. Just wondering if this is a feasible solution to my problem or if I'll end up with steam pockets in the head.

 

[Texasmark]

Re: 1971 mercury 800 telltale problem

Personally doubt relocating would do you any good/make any difference, and I am assuming that you are referring to the "water jacket" which covers what would be the head on most engins....Mercs of that era had no removable head.

I'd remove the fitting that attaches your hose that you cleaned out to the water jacket cover. Then run the tests as you previously did while observing the threaded hole in the water jacket.

If you still have no flow it means that there is no water in the jacket and looking through the hole to "the head" would yeild you a view of the head, rather than water which would certainly get hot upon operating the engine.

Dirt dobbers and other insects of the sort, are notorious for crawling up inside engines and blocking water passages. Dobber mud will usually get water soaked and come on out but the larvae could possibly clog a small hole. Other types, the ones that make the white nest are harder to soak loose, but they usuall make their nests in holes rather than a scab on a flat surface.

HTH

Mark

 

[Moody Blue]

Re: 1971 mercury 800 telltale problem

When running on muffs, you can only expect a little flow from the telltale. My 1971 Merc 800 with a brand new pump and impeller produces a dribble at idle on muffs.

My waterpressure gauge shows good flow when in the water so I'm not worried about it.

For piece of mind, I would remove the brass plug from the water jacket cover (located between plugs 2 and 3) and verify good waterflow. If you have good flow there, then you have an obstruction in the telltale line.

Moving the telltale output to the port on the waterjacket cover is probably not the best approach. A telltale at this location would rob some water from the cooling system. Maybe not enough to worry about, but. The factory telltale output is located at the "end" of the cooling system, and therefore does not divert any cooling water from the motor.

 

[breakingaway1322]

Re: 1971 mercury 800 telltale problem

Thanks guys. I figured it out ended up being sediment in the elbow coming out of the exhaust cover plate. I appreciate the help.