Straight gassed the saw

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saewoody

Feeling the Heat
Feb 15, 2017
456
CT
Well I clearly wasn't thinking straight. I think I was still in snowblower mode. I ran my saw on straight gas. It was pretty light duty cutting, but I used a tankful of gas. It's a Husqvarna 359 E-tech. I checked compression and it's holding at 157 psi. I put the correct mix in and cut a tank of with of wood with. Cylinder wall looks to have some scoring when I look through the spark plug hole. I haven't looked any further than that. Do you think I should just keep running the saw and keep my fingers crossed or do I do a tear down of the cylinder and replace it and the piston just to be safe? Your thoughts are appreciated. Thanks


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It's not only the top end that needs lubrication, the crank assembly and bearings need premix as well. So your damage could be more than a scored cylinder.

Was there any premix in the tank at all before you added the straight gas ? Even the smallest amount of premix will help. Or did you add straight gas to a completely empty saw ? Your compression is good. You only ran one tank with hopefully some old premix still in it before you started it up. Honestly if it were my saw I'd keep running it. It will let you know when it's tired.

If you do pull the cylinder spin the crank. Make sure the bearings spin freely and don't make any noise like grit noise etc. The lower end on those saws are durable and I believe can survive straight gas for a little while. Very little while
 
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There was some premix, but not much. Thanks for the response. I appreciate the input. I was leaning towards continuing to run it. I have a back up saw if this one does go down.


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The only reason I can think of to replace the piston now rather than later is that it might be a bit easier to do it now. Straight gassing does damage all the way around, not just near the exhaust outlet the way running it lean will do. If you start getting aluminum transfer all over the place then cleaning up the cylinder could become a chore.
 
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I would keep using it . As long as it performs up to your standards keep using it
IF it an't broke don't fix it
 
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Run it till it pukes.

I always mix my gas at .95 gallon of fuel to the synthetic oil container for use with a full gallon. Little rich is better than a little lean. If you run your saw in the very cold it's better for it as well.
 
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I would keep using it as long as your happy with its performance. If the top end dies on you I would use muriatic acid and scotch bright to clean up the jug and buy a new piston.


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Sounds like you got very luck so run it.

I would use muriatic acid and scotch bright to clean up the jug



Or do this and put a new ring in it.
 
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Sounds like you got lucky run it. Your compression is still pretty good.

Or do this...

I would use muriatic acid and scotch bright to clean up the jug

and put a new ring(s). $12-15, $20 with acid an scotch-brite.

It should take about 3-4 hours total.
 
As said earlier adding some more lubrication to your next mix would help. I have a friend who went to school through stihl, he had me mix in a little 5w 30 oil with my mix a few cap fulls. If the saw has engine troubles it will let you know, I would use it.