TroubleShooting Help

[fpangie]

Hi Gang

I've got a Stihl 015AV that I bought new back in 78. It was the only saw I had and I dropped and cut up about 10 cord of hardwood each year till about 94, which is when I picked up a Husky 55 to do the heavy work and the Stihl was my back-up. (In other words when I got the Husky stuck I pulled out the little saw). Anyway I was running the Stihl yesterday to do some light work and it started to sound funny, like it was loading up or maybe the plug was going bad. It wasn't long and it wouldn't run or start.

I put a new plug in it and it sputtered once or twice and that was it. It's getting plenty of air and fuel. Spark is another thing.... With the new plug removed and grounded, it sparks but very irregularly.

Is there a way of nailing down if it is the coil or the electronic ignition?

Thanks for sharing your wisdom.

Frank

 

[Gypo Logger]

Hi Frank, I hate to say it, but it sounds like a semi seizure sorta thing. Take off the muffler and check for piston scoring. If this is the case, the cyl. can usually be reclaimed with a new piston and rings. This kind of failure is generally a result of too thick of mix on a rich H screw.
Hope this helps,
John

 

[DDM]

Frank? your not running the same gas oil mix in the Stihl that you use in the newer Husky are you?
I'd imagine the husky uses a 40:1 or 50:1 and the
stihl probably uses a 16:1 mix which would explain the seizure after a similar experience i Marked
mix on all my 2 stroke equip.

Later,
David

 

[Walt Galer]

Howdy Frank,

Before you get too worried, check out the ignition. First disconnect the kill switch. If that did not fix it, try loosening and tightening the bolts that mount the ignition components, one bolt at a time, so you do not loose the ignition airgap setting. Simple old age and weather can corrode the ground integrity causing your problem. If you do screw up the airgap setting, just set a buisness card in there and rotate the flywheel to where the magnets are under the ignition coil laminations, and then tighten the bolts. This resets the air gap.

See my reply under the current post; "Ignition Module".

Fully 80% of electronic ignitions are replaced unnecessarily! (Past service school instructor speaking). Ignition coils may be quite another matter due to shorting between windings. Poorer quality ones will crack the varnish insulation between windings if more than 10 or 15 years old, and the ignition will weaken or die when the machine gets warm. (May run perfectly fine when cold!)

Regards,
Walt Galer

 

[fpangie]

Hey Gypo Logger / DDM,

The piston is by no means siezed, when I remove the spark plug and the pull cord, I can take the fly wheel and spin it freely with my fingers.

Walt,

I think you may be onto it with your ideas about it being ignition/coil. I have to admit that when I took it apart there was a lot of dust it there that I had to put the compressed air to. I will try your ideas, but here is some more info I found out. When I take an electrical resistance measurement from the spark plug wire to ground it reads very high (thats good), when I take a resistance measurement from the low voltage side of the coil (I connected to the wire 'tit' that the on/off switch rides on to ground, it looks like a short. Seems to me it should read as an open.

What do you think Walt?

Frank

 

[rupedoggy]

Remove the flywheel. Remove the cover. Clean the points and regap to .014-.016". Reinstall the fly wheel. Set module gap at .008-.012". Go back to firewood cutting. Mike

 

[Walt Galer]

Howdy Frank,

Remember that the primary side of the coil is only a few windings, and therefore will have very little resistance, and in fact will test about a short.

Regards,
Walt Galer

 

[fpangie]

Hi Rupedoggy

Thanks for the encouragement. I also want to thank whoever it was that posted the little trick on how to stick a piece of rope in the cylinder to jamb the piston so you can get the flywheel nut off. (I hate to admit it but I broke a fin off once upon a time using a less desirable technique).

Now I'm off the borrow a puller that will fit.

Frank

 

[fpangie]

Well Guys,

This time it's hats off to Walt Galer.

Walt I must admit that I never figured that my lack of spark would have been due to poor electrical connections on the low voltage side. There was no visable oxidation etc. It was dusty and oily in there. But... when I removed the screw that held the low voltage wire spade connector to ground there was some (not much) discoloration. I sanded down all the metal connection parts, set the module gap the way rupedoggy said and she started and ran like a dream second pull.

I never did pull the flywheel because it was going to take me another day or two to come up with a puller and I thought I'd give it a try in the mean time.

Thanks for the expert technical help. By the way, how long should the electronics hold up? I suspect they replace the points and are located behind the flywheel?

Thanks again....

Frank

 

[tony marks]

the man do know what hes talkin about dont he. later now