2nd tell tale for Mercury Mark 58 on top of motor

[rusty356]

Mercury Mark 58, the tell tale is blocked up and everything I have tried to open it up has not worked! I want to drill and tap another in the top of the motor, standing in back by spark plugs, I will drill in about center of top and to the left of the cylinders. Any one have a good idea where to located the top tell tale, besides where I am planing? Any help would be great. Rick

[gdcarpenter]

This is my auxiliary telltale tapped into in the top of the block

There is a water temp sensor in the tee for a water/coolant temperature gauge
One line out of the tee goes to a telltale outle and the other goes to a water/coolant pressure gauge

Hope this helps.

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[garry-in-michigan]

Great idea – a two for one solution. . . 😎

[Pondrocket]

Rick,

A couple questions before you head into this task. Motor in question what shape is it currently in mechanically? Has the motor been sitting for many years, how do you know there is blockage, do you have a few pictures to show the motor? These motors are perfect runners when properly set up and taken care of. Please explain what you’ve tried so far?

Travis

Travis
AOMCI VP Communications
AOMCI Webmaster
webmaster@aomci.org

[rusty356]

Travis: I have worked and got running at least 20 Mercury 4 cylinders, maybe more, on only 2, including this one, was I not able to get the tell tale to work. I have used wire, air pressure, with a small hole in the nozzle to make sure it got in. The other one, I could not get was a Mark 55, about a year ago, and it had had the water jacket off and the head jacket, I assumed that they got sealer into the hole and plugged it. But this motor, as far as I can tell has never had the head removed nor the water jacket, I rebuilt the mag, new bearing, new wires, timed it etc etc. It starts, runs and idles Perfect! But no tel tale, we worked for hours on the tel tale, maybe the water has by now softened up what is plugging it, but I am ready to drill and tap it, and I also have the 90 degree hose bib to install. Any ideas about unplugging it would be great. Rick PS we have also restored about 25 Mark 25’s, in last 10 years, but now only the Mark 58’s interest us.

[rusty356]

PS my direct email is: conn356@ecentral.com

[rusty356]

Motor has been sitting for many years, but no salt water exposure.
Rick

[dave-bernard]

when they are clogged that way you need to remove the exhaust cover and clean the passage out. may be clogged for inches. the bolts tend to break on the cover so I would not do it just add the top tell tail. if it opens up later you can just put a plug in the top one like the latter motors.

[rusty356]

Thanks, for the reply, that is exactly why I did not take the exhaust cover off! I suspected that some would break, and then I would be digging it out etc. Also even if it opens up later, I am happy to have 2 tel tales, no problem with that. Thanks Dave for taking the time to answer my question. I am going to drill and tap it! Rick Conn Foxburg PA
1

[rusty356]

Dave: I drilled it, tapped it, and ran it, lots of tel tale out of the new upper tap, just ran hose down other side, and out a hole. Love it. Thanks Rick

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