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1985 Mercury 50hp 4cyl potential cooling problem

R

rockinhitz34

Member
Took the motor out to start today and she ran great. Replaced impeller and gaskets yesterday, had a steady stream of water from the tell tale. I ran the motor for 15 minutes at idle and then shifted into fwd and reverse just to test. all seemed good. Tell tale water wasn't very warm which could be because today isn't very hot (~60F outside). However, I noticed that the upper exhaust port didn't have much water mist coming out.

I pulled the plugs to check them and they seemed OK, yet on the 3 and 4 cyl outside there was emulsified fuel/water on the case and outside of the plugs. Im wondering if I could have a head gasket/thermostat/cooling channel issue. Is there a good way to test powerhead temperature with a thermometer laser thingy? I have a seloc manual but they don't list normal operating temperatures. I just want to make sure I don't have a cooling problem before I run at speed in the water this summer.

Thanks, I appreciate the help.
 
There is a water jacket gasket near the sparkplug openings in the cover.----There is no head gasket on that motor.---There is no thermostat either.
 
racerone said:
There is a water jacket gasket near the sparkplug openings in the cover.----There is no head gasket on that motor.---There is no thermostat either.
Click to expand...

Ok, the manual I have is tricky because its for a bunch of different models. Is it worth it to take the spark plug cover off? Or am I better off testing temp first, and what temperature is in spec?

Thanks!
 
racerone said:
On a fresh water motor it might not be hard to remove the water jacket cover to have a look in there.
Click to expand...

Lived all of its life (until last year) in fresh water. Some mild corrosion but nothing crazy. Can I remove the cover without removing the powerhead? Just slowly undo all the bolts making sure I dont ruin any?
 
Im waiting on a digital thermometer to test running temp before I do anything. If I don't have a temp issue, can I run with a potential leak in the water jacket gasket for a few weeks? Don't want to fix whats not broken as long as Im not going to overheat the powerhead. Of note, I had serious corrosion on the outside of the spark plugs at the end of last season running in salt water, flush after each use.
 
You sure can. Careful application of silicone often reduces the leakage. I'd grease the wires and boots where any water might fall, just in case.

Jeff
 
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