Mercury Mark 6 Tale Tale?

[Buccaneer]

When I barrel tested my Mark 6 after overhaul I didn’t notice it
spitting water out anywhere. It only ran for about two minutes,
and the cylinders seems too hot.
I watched several videos on Youtube with Mark 6’s running
in a barrel, and didn’t notice those spitting water out anywhere
either.
Anyone remember if there’s a tale tale? The repair manual was
no help. I don’t have an owners manual, if there was such a thing
back in 1956.
Thanks, Buccanner

Prepare to be boarded!

[jasonh]

No tell tale .. They spritz water out 4 exhaust relief holes. I cup my hand behind the holes and look for water to collect in my hand. I also note temperature. There is a tube coming out from below the powerhead. Many confuse this for tell tale but it actually ia a excess fuel drain from crankcase.

[Buccaneer]

Thanks Jason. I didn’t notice water spitting out those four holes,
but will try it out again.

Prepare to be boarded!

[Buccaneer]

I dug my parts "Mark 6" out of buckets and looked at the water pump system today.
Having no tale tale was not one of Mercury’s better ideas 🙁
Pump discharge up to Pilot Cap on bottom of crankcase >
Into bottom of crankcase >
Out top of crankcase>
Into water jacket around cylinders>
Out bottom of cylinder jug>
Into and out of bottom of crankcase>
Dumps down into forward side of Pilot tube in exhaust stream,
and exits underwater

On the back side of the lower unit, 7-1/2" below the lower engine cowling,
are the four little weep holes grouped together.
Interesting, that when the engine is rotated 180 degrees, a 1/4" hole
in the pilot tube lines up with the four little weep holes.
I have no idea why it’s designed this way. The pilot tube only goes into
the crankcase one way, so it’s not backwards.

I put the Merc back in the test tank, fired it up, nothing out of the
weep holes, rotated engine 180 degrees, still nothing, engine
cylinders get hot right away…… guess the lower unit is coming
back off for starters 🙁
Perhaps I can test the pump in a bucket of water with a drill, but
not sure it will work with this model.

Has anyone ever rigged a tale tale up on a Mark 6? There are some
tiny core plugs in the cylinder jug on the cooling system that might
be possible to tap into for a tale tale.
Thoughts??????
Thanks, Buccanneer

Prepare to be boarded!

[Buccaneer]

Went back to the garage after super, had the lower unit off in about
three minutes…… wish it went back together that fast!
Stuck the lower unit in a 5 gal buck full of water, attached drill to
drive shaft, and yelled "Hit it"…….. I found that the spark plug
boot I put on top of the pump discharge tube for an elbow to
prevent getting squirted in the face, was totally un-needed!
Didn’t pump one drop. Yes, I was running the drill clockwise.
Started pulling apart the lower unit, and could see that the
impeller was turning as I spun the drive shaft by hand.
Check all passages from the inlets by the prop to the discharge
tube. All okay. Decided to pull the impeller out for further inspection.
Brass hub was somewhat stuck on the shaft. As I was trying
to pry the impeller up with a couple of little screwdrivers, I noticed
that the rubber was real loose on the brass hub, and it actually
pulled off the hub.
It was a $15 impeller from Vintageoutboard.com.
I remember it was a bugger getting that impeller started in the
pump housing. So, now I’m wondering if there was something
wrong with the fit of the impeller, i.e., oversized, too thick,
something wrong with the way the housings went together, or
just a back impeller.
Anyone else have problems with cheap impellers?
I see Crowley has OEM props for $24. Thoughts???????
Thanks, Bucanneer

Prepare to be boarded!

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