1973 Merc 200 (20hp) No Spark

[bakerp31]

I have a 1973 Merc 200 (20hp). I lost spark on both cylinders. I replaced points and verified properly set. I electricaly verified brown point wires at coil see points opening and closing. I electrically verified all ground wires are in good condition (with no corrosion). I verified plugs work properly by hooking them up to another motor and watching them spark quite aggressively. I checked the kill switch and it appears to be working properly (I have now jumpered it just to be sure). I have checked all the other wires and ensured that they are not broken or have worn spots that are rubing to ground. I am down to the condenser, stator, and coils. Neither of my local Mercury dealers (2) know how to check the condenser. They say replace it ($66) and see if it fixes the problem. I have a local electronics shop who can check it if I can find out what the condenser values are(voltage, capacitance, ESR, etc). Does anybody out there have any ideas on how to check the condenser or know what the values are?

 

[Greg Lawrence]

Re: 1973 Merc 200 (20hp) No Spark

heh i think throwing money at it would be easier.

 

[Walker]

Re: 1973 Merc 200 (20hp) No Spark

Not sure I understand what you did when you "jumpered" the kill switch. The kill switch works by grounding the ignition current. If you jumpered it then you have created the ground yourself. Unjumper it. walker

 

[bakerp31]

Re: 1973 Merc 200 (20hp) No Spark

If money was not an object, I would give this one away and buy a new one.<br /><br />On this 1973-200 the Kill switch is a button that actually provides the ground for the ignition. When you push the kill button it opens the circuit. Mercury considered this a fail safe design (bad or corroded ground or broken button, no spark). I had to look through the manuals several times before I would believe it myself. Any other ideas???

 

[dmessy]

Re: 1973 Merc 200 (20hp) No Spark

A quick condensor check is to ground the cond. wire to get rid of any charge, then use an ohm meter connecting 1 lead to the cond. wire and the other to the cond. metal housing. The needle should jump up then bleed back. No resistance?open cap. replace...high resistance without bleed off..replace.

 

[dmessy]

Re: 1973 Merc 200 (20hp) No Spark

Also, back track that ground wire... I had a Merc. 20 that gave me fits because the brown ground wire was broken internally, thus causing a open circuit. Yes we both know that the kill switch MUST be grounded on this particulatr motor. Funky design, and it'll shock the beegeesus out of you when it gets damp on foggy mornings!!