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synthetic oil on old 18:1 chainsaw?

radioconnection's Avatar

Join Date: Aug 2006
Posts: 902

11-25-07, 01:33 PM   #1  
synthetic oil on old 18:1 chainsaw?

Can I use the newer synthetic 2 cycle engine oil on my older Jonsered (sp?) chainsaw? It takes a 16 or 18:1 ratio, much lower than the new stuff. How do I determine the correct mixture?


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geogrubb's Avatar

Join Date: Jun 2006
Posts: 2,333

11-25-07, 03:30 PM   #2  
The old 2 cycles will run on any oil designed for 2 cycle engines, the newer oils are designed to give proper lubrication and meet the EPA requirements at a 40:1 50:1 ratio.
To calculate the measurements divide 128(ounces in a gallon) by the ratio ie. 16 for 16:1

128/16 = 8 , so for 16:1 you need 8oz. oil to 1 gal gas
128/32 = 4 , so for 32:1 you need 4oz.
128/40 = 3.2 40:1 3.2
128/50 = 2.6 50:1 2.6

puey61's Avatar

Join Date: Apr 2004
Posts: 3,224

11-27-07, 11:45 AM   #3  
If you had the original owners manual for the saw you'd also find that the recommended oil was SAE40 engine oil, not 2-cycle oil. I've had good luck with Opti and AMSOIL synthetic oils in all two stroke engines. Never once had a return with a seized engine using either of these oils, even with the old Homelite chainsaws that called for the 16:1 ratio with 40 wieght oil.

bontai Joe's Avatar

Join Date: Apr 2004
Posts: 592

11-30-07, 06:44 AM   #4  
So you guys have had good experiences with the new synthetic oils in a 2 stroke? Any other advantages besides it runs well, like the mix being more stable if stored a while? etc.? I ask because I'm totally ignorant on synthetic oil in this application.

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