No spark - 1963 Mercury 650 - magneto OK?

[dtmille2]

Getting no spark, changed the plugs, not sure what to check next.

One question I had is related to the grounding wire on the magneto -- it measures 0.5ohm resistance to ground whether the switch is "off" or "on". I thought with the switch off the resistance to ground would be much lower than with it on.

Any thoughts?

 

[racerone]

Some will argue.----It takes just 4 screws ( 3/8" wrench I think ) to remove the bottom half of the magneto.-----Then remove cap and rotor.------Clean and set breaker points at 0.010"------Test for spark before re-installing the bottom half back onto the motor.----Careful as some parts are expensive.------Yes , the resistance should be different with switch on or off.

 

[dtmille2]

Thanks! Might give that a shot in the morning.

 

[Quicksilver]

When you're measuring at the stud you are reading the primary coil resistance but when the switch is turned off it should reach 0.
There's a wick that lubricates the cam, if it's worn out get a new one or pull the old one out and turn it around. Without it the points can stay closed after a few hours. This site has hundreds of guys who know magnetos http://johnsoldmercurysite.com/phpBB3/index.php