Stihl 084 won't start

mgood61

I am new here but here goes. I have a Stihl 084 that stopped running the last time I used it and won't start again. During a cut, it slowed speed then shut off. It has spark and is getting fuel. I even poured a little in the carb to test that, then in the plug hole, but nothing. I have not tested compression since I don't have a tester, but I am leaning towards that being the cause. Any ideas?

rick

How does it turn over ?
Does it feel like it still has reasonable compression ?
Have you pulled the plug and had a look at it ?
Was there anything 'extra' on the plug ?

Pop the muffler off and have a look at the piston, that'll tell you pretty quickly if things have gone south inside.

mgood61

It still has good feel for compression, and I can feel a difference when I push the compression release. Pulling the muffler shows wear, but no scoring on the piston. I put in a new plug, and it is firing, but there is nothing on the plug, including any carbon. Almost like it isn't causing any ignition. That's why I put some gas mix in the plug hole to try and eliminate the possibility of a carb or fuel line stoppage. Even then it didn't even hit like it was trying to start.

Bruce Hopf

Another possibility, is that the Cylinder Gasket, could have a leak, or the cylinder it self could also have a slight crack in it too.
I had a Perkins Diesel, have the same thing happen to it, as your chain saw.
What caused the problem with it, was that it had a crack from one of the head bolts over to the piston wall. and that motor wouldn't run at all.
What I'd suggest is to pull the cylinder, and look. Also check the cylinder wall for internal damage. There is a Ni, or Ci coating on the cylinder running surface, that might have flaked off slightly, or worn off slightly, that would also cause the trouble.
The best thing that you should do, is to pull the cylinder, that way you will be able to check everything internally. Bruce.

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terry

i had a similar problem with an 046, i took it to a stihl dealer they told me it was the magneto,it had spark but wasn't strong enough to fire it.

MrDiesel

I agree with Terry check the magneto and make sure its an even space between both ends. Check the wire to the spark plug to make sure its not r/s