Stihl 034 no start

Have a Stihl 034 that refuses to start. Checked all the usual,coil was weak,replaced it and now have good spark,compression is over 160 after 5 pulls .The carb was gummed up,I cleaned it and put new kit in it.It wont even run after putting a little gas directly in spark plug hole. New plug is good,runs fine in my other saws..Piston is scored slighty in ring area on the muffler side but it has great compression.. Flywheel key is not sheared,looks good. Guy who owns had put a 4 cycle sprark plug (Autolite 258) .Way too hot heat range ,melted the center out. Im using the correct plug now,great spark..Will not start or even sputter,what am I missing?? Thanks for your help.
 
If the owener burnt the center out of the spark plug and you said it had some scoring I bet there is more scoring than what you saw.To burn a center out of spark plug she got damn hot.
 
Burned out spark plug? Might as well tear it down. You got a trashed motor, more than likely. I've seen some really badly scored cylinders and seized rings show decent compression. Hope you didn't pay much for it and if you paid more than $20, you paid too much.
 
rings locked up, cylinder scored. takes new piston, rings & cylinder; or muffler plugged. Take the muffler off & try to start it.
 
Unless you are real lucky and the muffler is plugged, it's time for a rebuild.

I don't know why the heat range of a plug would "melt the center out" of a plug. If it's melting the steel and ceramic out of a plug it should have melted the piston too. I could see the plug getting smashed by the piston though if it was the wrong plug. I'd like to see just what the plug and piston top looked like.
 
From every thing you said you have did to it the only thing left to do would be put a new jug and piston kit in it.If you look on Ebay there are about a dozen guys selling jug piston kits from $40.00 to over $100.00. If the rest of saw is in real good shape a new jug piston is way cheaper than a new saw ( depending on how you gave for saw).
 
Muffler not stopped up,gutted in fact.Teddy, 85 psi compression on one pull of the rope,4/5 rev. maybe? Spark plug that was in it was for a 4 cycle lawnmower engine ,heat range way too high for this engine. I guess the next thing is to pull the cylinder off and take a look. Just seems like it should burn the gas I put in the plug hole ..Good thing is ,its not my saw. Thanks for your help,will keep you posted on the next move.
 

If your compression is only 85psi on the first pull it's toast. It should be up about 130-140 at least and build a little from there. Under 100lbs on the first couple revolutions is not good.
 
The plug that started it all, I think.
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Holy smokes. Pull the jug. I bet the top of the piston is history.

Are you SURE that wasn't a plug the guy just put in there? Looks like someone tried " fire cleaning" the plug with a O/A torch. I've never seen anything like that come out of a running chainsaw, but I make no claim to have seen everything. If it win thas actually e saw when it was running then you have to figure all that molten metal wrecked the piston and probably the jug.
 

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