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Joined:  Oct 2008 
Posts: 43  
Novice 
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I use a chainsaw, mowers, brushcutters, and a small mulcher. What is the best mix? At the moment I am using high octane petrol, and Stihl 2 stroke oil at 25:1,  I am worried about damaging my smaller engines through carbon deposits on  moving parts. Fuel mixes recommended are rated at: 25:1, 40:1, 50:1. The Stihl oil is recommended at 50:1 but I have only one good jerry can. I run my car on high octane fuel and synthetic oil. It seems to have better torque response with high octane fuel; the gears are not matched well to the small Korean car engine design, high power, but low torque. Any ideas folks? 
 
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Joined:  Aug 2007 
Posts: 549  
Chainsaw Addict 
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I just use Stihl 2 stroke oil at 40:1 for everything which includes 40 year old chainsaws, I think Stihl 50:1 oil mixed at 25:1 could cause carbon deposit problems.  I don't use high octane petrol, just the standard stuff, so far no problems.
  cheers gmax 
 
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Joined:  Oct 2008 
Posts: 43  
Novice 
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Some old car manuals used to recommend a high speed run at high revs to remove carbon from valves, guides, heads etc. BMW for example. I think Stihl is mixing fuel with oil to get better response on 4 stroke engines for small machines to improve emission standards. Cheers gmax. GOOD idea! 
 
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Joined:  Dec 1999 
Posts: 5,387 Likes: 34  
Repair Junkie 
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gmax, I have been running smokeless two stroke in all our equipment including the 4 stroke engines for over 20 years now and no plugs carbon up at all.     
 
 
Regards,           ![[Linked Image]](https://www.outdoorking-forum.com.au/forum/images/members/mower-monsterw.jpg) Bruce                               Please do not PM me asking for support. Post on the forums as it helps all members not just the individual. 
  
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Joined:  Aug 2007 
Posts: 549  
Chainsaw Addict 
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Bruce,
       Is that a synthetic oil ?
 
 
 
   cheers gmax 
 
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Joined:  Jul 2009 
Posts: 16  
Novice 
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I have been using 50:1 in my fuel for 10 years and I find no problems with my Stihl and my recently Tanaka. I still got my Stihl FS44 for 10 years and I service it regularly. The mowers I do up didn't hurt either particularly The Power Torques 2 Strokes. My Main Current Mower, A Victa Mustang Mulch & Catch 5HP 4 Stroke Tecumseh runs on Normal Unleaded. I tried the E10 But I wouldn't recommended it because it had the hiccups and I put her on the 98 Premium Unleaded and she's running like a dream on it. No foul ups either. My Stihl & the Tanaka runs also like a dream on the 98 Premium Unleaded Fuel and I had no Foul ups either. Thanks.
  Regards.
  David.  
  
 
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Joined:  Apr 2009 
Posts: 288  
Apprentice level 3 
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hi all,  I have tried many many brands of two stroke oil and would recommend penrite for 25:1, 20:1 ect but have found that echo make a awesome oil for 50:1, it has low smoke, low ash and doesn�t stink like the rest, and best of all its very dark green so you can actually tell when its mixed. I only use regular shell unleaded and have never had a problem yet, but i would NEVER recommend Caltex petrol because its low quality stuffed my injectors in the tractor (they were only 2 months old). also if you can find one or two liter dangerous goods containers, you could mix a little of each individually.  regards jay 
 
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