# McCulloch Power Mac 6- no fire, no start



## n9viw (Aug 18, 2009)

I am in the process of attempting to resurrect a '71 (13-600086u) Power Mac 6, and having trouble starting it. The compression is good, rings look good, carb was recently cleaned and in good shape.

I have not yet changed the plug, but it bugs out as good (non-resistor Champion D6). I'm getting fuel into the cylinder, as plenty unburned fuel is spitting out the exhaust port. I pulled the plug, wiped it off, plugged it in to the HT lead, and held it to the head while pulling the cord- no spark, though I about pulled myself breathless and the engine spun brilliantly.

I pulled the flywheel and inspected the points and cleaned them. They were in good trim and proper gap, with no marking to indicate a bad condenser. Wires were in good shape too, kill switch moves fine and does break contact.

About the only thing I can think of is the coil (magneto). When I removed it to pull the carb, I was a bit confused about the nylon sleeves insulating the mounting screws from the coil body; after all, the coil body touches the carb. The carb seems to be electrically isolated from the head by a composite port, but may be grounded by the throttle rod, I can't tell. 

The coil is very close to the flywheel, I actually had a difficult time ensuring a gap so it wasn't physically dragging on it, and there was no method of adjustment. The magnet on the flywheel is plenty strong. I used a bit of cardstock to 'gap' the coil lugs from the flywheel while I tightened the screws, then pulled the cardstock out. The flywheel does have marks on it near the magnet that evidences contact with the magneto, probably not a good thing.

Also, there are two wires coming from the coil- one goes to the points/condenser, thence to the kill switch. The other is pinned to the coil body by one coil mounting screw, effectively (IMO) grounding it. Am I missing something? I've not been able to find anything specifically regarding this setup in the few manuals I've tracked down (mostly owners' mans and IPLs).

So, good air, good compression, good fuel, NO spark, so PM6 no worky. Any suggestions (NO, I will not use it as the world's lightest boat anchor! :tongue are appreciated.

Regards,
Nick :dude:


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## 30yearTech (Sep 14, 2006)

The coil is not isolated electrically from the engine. The wire that attaches to the mounting screw is for the ground. Coils are reasonably dependable and rarely fail. I would check for good continuity on the contact points, and make sure there is no short to ground on the condenser or kill switch lead wire. I worked on a ton of these saws back in the early days when I first became a small engine mechanic. It's very easy for the condenser wire terminal to ground out where it attaches to the points, and many times points will be closed but will not complete the circuit.

Best of Luck....:thumbsup:


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