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Old Merc

The 3 cylinder motor first built in 1972 ( 2 carburetors ) was not one of the better offerings from Mercury.-----If you own one then you must keep the cooling system in tip-top shape.
 
This is a 73 3 cyl 2 carb, 130psi on all 3 has no spark. Put a used dist off a 1975 650 that was running so the guy said and still no spark. Dont know how to check dist or switchbox.
 
spoken like a gentleman racer.....i would not be so tactful....had a fishing buddy ran and worked on one for years....refused to get rid of it....we rotated boats....finally said enough and refused to get in his boat til he replaced it...
 
People have differing opinions on motors,some are more vocal than others.My opinion is everyone to there own."One man's meat is another's poison."
Back to your motor,as racerone says these were prone to cooling issues,so keep an eye on that.
Your no spark is probably down to a bad switch-box.But before replacing,check the mercury tilt switch,small cylinder like thing,won't be far from the switch-box.Disconnect it and turn her over again.
Switch-box can't be checked with a multi meter,but if everything else works out,then it's your switch-box.Could you borrow one from a known running engine?
If there are no cracks and the wires and guts look good,it is unlikely to be the dissy
 
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I'm 99 % sure it's the switch box, but try this first: Find the tilt switch (little mercury switch that shuts the motor off when it tilts up) and cut/ tape off the wire. Then re-check for spark.

Jeff
 
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