25:1 mix
- Thread starter dugide
- Start date
Help Support Arborist Forum:
Are you sure the mix caused it?
I had a guy telling me the other day that you can lean a saw way out as long as you kept the oil up. Could this guy have lean seized even with a heavy oil mix? Was he using high quality 2-cycle mix or straight 30?
(just speculating - interested to hear what others say)
Philbert
I had a guy telling me the other day that you can lean a saw way out as long as you kept the oil up. Could this guy have lean seized even with a heavy oil mix? Was he using high quality 2-cycle mix or straight 30?
(just speculating - interested to hear what others say)
Philbert
stihl for life
ArboristSite Guru
wierd ive never herd in my life time u can score a saw on 25-1 .. i mix mine 40-1 or when i buy ams oil and octain boast . i mix it at 80-1. have had no problems logging with these mixes
Guido Salvage
Supreme Saw Whoreder
I usually score my saws on Craigslist...
Stuck rings and carbon build up seem to be likely drawbacks of 25:1. Homeboy needs to fix his saw and then get with the 21st century, I reckon.
It's a trap. Don't say anything.
oke:
oke:
zogger
Tree Freak
I doubt it, more likely a common failure, rank mix, older 346 with the plastic clamp/leaky boot, whatever.
My unscintific splanation to this is heavy ratios lead to more problems based on the fact the mix doesn't get the chance to flow like it would at 45-1 or 50-1 25-1 it hangs in one place to long letting it slow burn and stick things leading ot other issues down the roadopcorn:opcorn:
opcorn:opcorn:
7sleeper
Addicted to ArboristSite
That is complete humbug! It has to do with the two time combustion in the chamber. First combustion is the highly volatile gas component. Second combustion is the inert oil combustion. Due to the low oil content the second inadequate combustion is working contrary the acceleration of the piston, kind of like building a combustion void => sticky ring syndrom!
You listen to me! I tell you!
7
You listen to me! I tell you!
7
514mach1
ArboristSite Operative
Was probably run lean. Doesn't matter if there's plenty of oil, it'll still get way too hot for the piston/ring if it's lean. But the bearings are probably fine! If it was scored all around the piston, maybe he was just running it without the air filter.
7sleeper
Addicted to ArboristSite
husq2100
Addicted to ArboristSite
the only way to add more oil is to do it in the mix. So now you have a greater oil to fuel ratio. This in itself is leaning out the saw. So if your saw is tuned to 50-1 at your altitude, then you lean the settings AND change the mix to 25-1 you will be double leaning out the saw. Good luck with that.
You can pretty much run any ratio from 25-1 through to 50-1 as long as you tune right for the particular mix. More of a variable is the quality of fuel, the quality of oil. The age of these, has it been sitting in the saw for months,how clean the air and fuel filter are, etc.......
I ran with an outfit that used 25:1 and the exhaust fumes were just brutal in winter.
Scooterbum
Addicted to ArboristSite
Stephen C's explanation is dead on. More oil = less fuel = leaner mix.
I've been running saws @ 25:1 for 30 years!! and have never even marked a piston!
Redbug
ArboristSite Member
I run 40:1 in my saws, weedeaters, and blowers. all the same mix.
That's very interesting about 25:1 making a leaner mix. I would never have figured that.
That's very interesting about 25:1 making a leaner mix. I would never have figured that.
gmax
Addicted to ArboristSite
Just don't run 25:1 In a BG 85 blower, the spark arrestor screens don't like it.
SawTroll
Information Collector
More oil makes the fuel to air mix leaner at the same carb setting, as the oil displaces fuel.
Oooops - I see others already had posted that....
Last edited:
