I believe in using 2 cycle oil designed for air cooled engines in such engines. I mentioned using from 15 to 1 to 50 to 1 in this tread and past threads and I have mentioned I understand many successfully run 50 to 1 which I attribute primarily to better quality oil. I have read through most of the oil threads and I have concluded that what I have found out is 25 to 1 has worked best for me for what I do without getting jibberish and bringing 5w and 90 weight into an 2 cycle mix discussion. I learned what I know by experiance and observation. No matter how scientific this or any discussion gets , I have learned common since always is necessary to understand the point of the matter. Lets try to bring to light what some of you may being trying to make sense of concerning the oil to gas mixture and fuel to air relationship.
Say you run 25 to 1 (oil to gas). Properly tuned ( air filters not clogged,ignition system works fine, and you have adequate compression,no air leaks ,etc.you adjust the carb metering screws which adjust the fuel to are mixture so that your saw is near maximum performance without exceeding max rpms.Not a specific rpm except less then max where your saw pulls best and starts well and your plug should be light tan or close to it in color. ( This is how I aim to maintain my saws and it works very well and I run well used mostly stihl saws)
Now say I mixed 50 to 1 (gas to oil) tomorrow. The science is 25 to 1 is thicker (using the same oil) Now I put 50 to 1 in my saw.To get the same flow rate of fuel to airthe thinner 50 to 1 mix is going to flow faster through your carb(so apply some more science) so you must re adjust your carb fuel to air mixtureto get the maximum performance with out exceeding max rpm on the new 50 to 1 mix ratio, like I did when I adjusted it the first time with 25 to 1.
Ok, I notice less smoke at cold start but after a couple cuts I would think I notice little difference then yesterday( some yes but little because when my saws are properly tuned they burn clean enough I barely see smoke if I do at 25 to 1 cutting.) Judging from past experiance my old ebay rattletrap 026 would feel not quite as powerful as yesterday after a good warm up round or 2 switching to 50to1 probably because its borderline compression and the extra oil at 25 to 1 was helping it out increasing compression,reducing frictiion and burning nearly as clean as the 50 to1 and certainly clean enough where I have no heavy carbon build up over many years or probably thousands of hours. The 044 I bought of ebay feels significantly more powerful to me this year then last after I purchased it and I attribute most of that to the effects of extra lubrication doing a better job then when it was probably getting less from its previous owner.
Probably a new saw would not utilize the benifits of 25 to 1 like my older well used saws and if you didn't keep your saw well tuned there is an advantage of less carbon if your making enough to cause problems and if your engine tuning is causing excess smoke you will have less at 50 to 1 comparing apples to apples tuning with each mix. And am not ignorant or in denial that carbon build could build up on top the piston and start hammering on the head destroying the top end. Its never happened to me though, I've seen it in shop manuals.
I wish I could have learned something from my grandpa's,but they died before I could ride a bicycle. I learned from my own experiance trying differant things and consulting with the best mechanics I knew and observing information provided to me in manuals and actual oil ratio test. I worked a couple years in a motorcycle shop and a week of training covered oil including 2 cycle mixes.
No claims to infinate knowledge,but I have found not forsaking what knowledge I have a better option then taking advice over my knowledge. That many times has cost me problems in the past in other life experiances thinking that anothers advice exceeded my previous experiance.
I hope I haven't been confusing to anyone and please don't struggle trying to understand my points
( It looks simple to me and I think it should to you all to)if it doesnt make
sense to you.
IN short I am not saying any one ratio is best always. I believe you can do well from 16 to 1 to 50 to 1, maintnence and tuning of your engine being the by far the most determining factor in what is best. Under or over these ratios you can very easily begin to have problems due to the extremes of either effect with todays average air cooled 2 cycle oils. Your very best oils availuble may do better then that , but I cannot afford to go that route in the case I had reliability problems. If I had new saws under warranty and they said to use less oil it would be differant.
Hope you all enjoyed another mix ratio post and do the right thing for you.
