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1968 Merc 60 not Circulating Water, Impellor OK

971821

New member
Motor started spitting water intermittently. Pee hole clear. Eventually slowed to nearly nothing.
Took home, flushed with water hose and flush attachment. Good back flow but still not pumping.
Dropped lower, expecting to change impeller, but visually ok. Spun shaft with drill in bucket to confirm pumping.

Hooked hose to water pipe to simulate pump flow but still no flow out pee hole. With compressed air forced up into the water pipe, it did push some remaining water out pee hole.
Fresh water only for life of motor. No mud/junk.
Does this thing have a thermostat? Did not think so.
Do not want to take completely apart unless necessary.
At a loss for ideas.

Ordered a service manual. Will take a week.
Kinda need this working.

Anyone with ideas how to correctly troubleshoot this in the meanwhile?
 
No thermostat.-----When these motors have a severe overheat ( happens a lot )----- There is a plastic washer at the top of the water tube.------Have seen this washer melt and block waterflow to the block.-----Replacement washer is a better material.-----Powerhead needs to come off to inspect.----Fairly easy to do in my opinion.-----Not saying that is the problem but should be checked.
 
Thanks racerone.
What do you think about a test of this theory by pushing a hot wire up thru the tube and see if it melts a hole? Any harm?

Anything else to look at short of pulling head? Could there be any water jacket problems if it flushes? Wish I had a diagram to show how this is plumbed.

If no other solutions come, I will probably wait to pull it after the service manual arrives.
Are new gaskets usually required when pulling heads on these old motors?
 
Don't pull the head until you're sure the Tell Tale is clear.

Jeff

Thanks Jeff, from another Pa guy.

There may be some junk inside the cooling jacket, but the hole is clear. It will piss out left over water when under some undetermined high air pressure, but not under, a guessing, 10-25 psi water pressure, when hooked up directly to the water pipe. Did this laying its side.

Am I in danger of snapping bolts when pulling a head on one of these old motors?
 
Racerone:
Are these the parts mentioned that melt at the power head end of the water tube?
The first one (#40 on lower schematic) is the same at both ends.

Bottoom cowl and adaptor plate:

[url]https://www.perfprotech.com/mercury-marine-parts-catalog/bottom-cowl-and-adaptor-plate/assembly/399/12?model=1033


WASHER, NYLON - WATER OUTLET TUBE (ADAPTOR PLATE) (#23-13127) and [/URL]

SEAL, RUBBER - WATER OUTLET TUBE (ADAPTOR PLATE) (#26-36556)



GASKET, POWERHEAD PLATE (#27-89937)

SERIAL #2080069-09999999
Fastjeff, I take it these are the 2 gaskets I need?

GASKET, ADAPTOR PLATE TO DRIVE SHAFT HOUSING (#27-39050)
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I would like to have my needed parts before tearing this apart. Any thoughts on best place to buy these online? Oldmercs?
 
Your local FRIENLY dealer for MERCURY motors will likely have these in stock.------These parts were the same year after year !
 
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