no spark coil and spark plug changed 2 times

[earnman]

husquavarna 440 chain saw out of blue chain saw stalled .. no spark replaced plug.still no spark.. replaced coil still no spark replaced a second coil and plug still no spark.. tested ohm on coils to ground and to coil 4.85 ohms .. i disconnected wires from coil still not spark.. replaced fly wheel still no spark..tested with spark plug out grounded plug to block still no spark????
help please

 

[Bob Hedgecutter]

Are you sure the starter is engaging the flywheel and actually turning the engine over?
What happens if you put a drill on the flywheel nut and check for spark?
Can you turn the flywheel WITHOUT turning over the engine?

Chainsaws do not just out of the blue stall- it did so for a reason.

 

[earnman]

yes engine is turning over i see piston going up and down ..
yes i agree they just dont stall and no spark for no reason

 

[Bob Hedgecutter]

yes engine is turning over i see piston going up and down ..
yes i agree they just dont stall and no spark for no reason

Yes the engine turns over- but is it turning over by the starter unit- or is the flywheel spinning on the crankshaft? Is my query.
Trying to eliminate a shorn flywheel key/loose retaining nut.

With all the coil swapping that has gone on- what is the air gap set at?
Where did the replacement coils come from?
Plugs are good quality plugs not TORCH or some other kind of imitation crapola?

 

[earnman]

yes engine is turning over i see piston going up and down ..
yes i agree they just dont stall and no spark for no reason

air gap 8 thou got coil and fly wheel from husqavara also plugs

 

[Bob Hedgecutter]

Without doing the math- guessing 8 thou is close to 0.3mm.
Right so if you say all is correct mechanically- only thing it can be is a fault in the wiring system.
Damaged HT wire or connection inside the boot from coil to plug, or permanent to ground on the kill switch circuit.

 

[earnman]

i disconnected wires from coil??and still no spark

 

[Bob Hedgecutter]

Only one wire from switch needs disconnected- eliminates a faulty switch.

If you have replaced all major components properly- flywheel, coil and spark plug- with genuine new products from a Husqvarna agent- then if you have not seriously goofed something in assembly- how can it not spark?
Maybe take the saw back to the agent you got the parts from and ask them?

At the end of the day- its a pretty simplistic system- not much apart from parts failure can deaden it and you have replaced all the parts.

 

[earnman]

yes i agree very simple system thats why i am on this forum i ordered parts through a husqvarana online