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Post by brians2n on Apr 10, 2014 11:28:29 GMT -5
I really feel ignorant admitting this but here goes anyway...
I was looking on Saw Collectors Corner and noticed the fuel ratio for my 7-21 and EZ listed as 10:1 and went huh? I never did the math! I grew up with the XL-12 and the ratio was 16:1. I never gave it a thought obviously that 3/4 of a pt is 12 ozs. Sheesh! I feel like an idiot now. So I have been running 16:1 in my 7-21 for quite a few hours. I am hoping I have not been damaging anything. Please someone tell me that it is fine to run 16:1. I am still going to feel stupid but be that as it may...
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dynodave
Saw Builder
equal opportunity GEARHEAD
Posts: 246
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Post by dynodave on Apr 10, 2014 12:42:38 GMT -5
I run the same stuff in all my 2 smokes...new and old saws, string trimmers/weedwackers and leaf blowers...about 40-1. The only difference for me is I run E-10 in tools that I use often and drain it if I'm not going to use it for a while. I always use E-10 stabilizer in the E-10 fuel.
As you probably know, you can almost not get gasoline anymore and can only find "EPA" approved "spark ignition fuel"..... AKA E-10.
For occasional use only, I use airport 87 octane real gasoline again at 40-1. Then I don't have to drain it.
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Post by brians2n on Apr 10, 2014 18:45:09 GMT -5
OK, I feel better then. Apparently not that critical...Great! Thanks for your input and the peace of mind.
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Post by lesorubcheek on Apr 10, 2014 21:28:55 GMT -5
There's been a bunch of debates about oil over the years. It's been said that older saws have looser tolerances and should have more oil in their mix than newer ones. Most seem to agree though that newer oil is just plain better than older mix oil. I'm in the same camp as Dave. Pretty close to 40:1 in everything, old or new. There is still alcohol free available in these parts, so try to use it for all the saws. So far, no issues whether its a Wiz or Zip, a 750 or 8800. Personally I think a good modern oil at 40:1 has all the lubrication any saw needs. Just one opinion though... many may well disagree. My personal opinion is it's more important to make sure the carb is adjusted to whatever mix you're using. 4-stroking at WOT out of the cut and cleaning up in the cut under load.
One really important fact I learned on these forums is that more oil means less gas in a unit of volume going through the engine at any given time. That means if you're running 40:1 and then switch to 16:1, you'll need to open up the H jet to get the same amount of gas. Again, very important to adjust the carb propery for whatever mix you use. Another reason it's a good idea to keep the mix ratio the same.
Dan
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Post by sawnami on Apr 10, 2014 23:29:00 GMT -5
Let me really scare you.  I run 92 octane ethanol-free gas with a well known synthetic oil at 50:1 in everything that I own. Never had a problem. Oops, I forgot that a couple of them get 110 Sunoco at 50:1.  |
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Post by Supercharged86 on Apr 25, 2014 19:04:39 GMT -5
Oops, I forgot that a couple of them get 110 Sunoco at 50:1. Nothing like race gas, even if it's $14 gallon. |
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