Fuel Oil Ratio

[ArborView]

I've always used a 40:1 mixture for my Stihl 034 because that's what the owners manual recommends. However the Stihl oil I buy now is setup for a 50:1 ratio (6.4 oz to 2.5 gallons). I'm assuming this ratio is for the newer saws and I should stick with the 40:1 for mine. Is this correct?

 

[TonyM]

Personally I run my saws at 32:1, even with the newer saws and oil. I have seen tests done in motocross magazines that show that the lower the ratio, the more power the engine makes, up until the plug begins to foul. I have not yet had to change any plugs (approaching 100 full chord of firewood on two saws). Seems to me the little extra oil will help ring and bearing life as well.

 

[confused]

whats this mix rate then for 32:1?

 

[TonyM]

128 ounces/gal

128/32=4 ounces oil (per 1 gallon)

 

[dbabcock]

Ken D. recommended 32:1 to me for my modded saw, but I'll be using that ratio in my others from now on as well. One thing that I'm going to also do is change to synthetic. I just ordered a couple of half gallons of Maxima 927,which is actually half synthetic polymer and half castorbean, also endorsed by Ken. It's more expensive than regular name brand petroleum-based oils at about $34.00/gal., but based on my previous experience using it in race outboards, it's money well spent.

 

[confused]

yeah everyone seems to say run it at 32:1 so i will be from now on i just have to get out and tune the motor to the new mix though. I'm going to stick with Stihl Pro oil though unless there is something better.

 

[Gypo Logger]

Hi There, Ken made an interesting point about 50:1, and that it has more to do with emmisions control than anything else.
Since 99% of saws are not set up properly on the carb anyway (rich or semi fixed jets), than the 50:1 is adaquate, however for the few of us that like to defeat semi fixed jets and run a little leaner on the high, than 32 or 40:1 may be the best way to go for that added insurance. I have always run 50:1 since I can remember, but now that I am using modified saws I will take Ken's advice.
John

 

[Toneman]

Good points guys. I think I'm going to switch over to the 32:1 ratio too. This will allow me to only have one container with fuel oil mix, and more importantly, more protection for all my 2 strokes!

 

[tony marks]

just wondering if the 50-1 mix doesnt foul the plugs at the
ingrease of oil in the mix. i mix standard way ,so just wondered.
later now

 

[rbtree]

Tony,

I've had no problems with plug fouling, nor do I notice an increase in smoke. I too switched to 32-1 on Ken's advice months ago.

 

[tony marks]

thats interesting. ill give it a try on the 28 .later now

 

[confused]

On my 046M to tune the saw all i have to do is turn the high setting till it four strokes a bit right. I have never messed with any of hte setting on my saw so pardon if im a bit moronic.

 

[HUSKYMAN]

I mix at 32:1 for the simple reason it will cover all my saws, from the old Homlite XL2's up to the "new" 55

 

[Fish]

I am amazed no fight has erupted from such a
volatile topic. I have never seen so many here
agree on one thing. I admitted I used 32:1 in
everything on the TSF and got all kind of abuse
last year. It even muffles out my saw's pinging.

 

[ricksvar]

Hi All,I'am using 50:1 mix,seems to do well on all my new power equip which is factory original with no modifications.A 50:1 mix should produce lower emissions and with 2.6 oz. oil added to a gallon of fuel have less effect in lowering the octane valu.

 

[TonyM]

One thing I learned from off road motorcycling that I thought was strange but at the same time made sense is that if you increase the amount of oil in the mixture (say from 50:1 to 32:1) then you actually are leaning out the engine (More oil means less fuel in the same volume) Changing mix ratio does require adjustment to the carb, and once you settle on a ratio and carb setting, you should stick to it. Two stroke motorcycles come notoriously rich from the factory (To cover the manafacturerers rear end against engine failure warranty claims). Often these engines foul plugs when ridden in trail situations, and most novice riders will mix less oil in their fuel in an attempt to remedy the situation. This actually will make plug fouling worse in most cases. The jetting needs to be changed, and once you get the jetting right on a two stroke engine, it should not foul plugs.

 

[dozerdan]

Fish
I have run 32/1 in all of my saws since the early 70s without a problem.If you would use some good fuel,you would not here that ping.LOL.But seriously,I have never heard a saw ping,have you?
Since you are the main instigator here and you are always picking on poor little otto,what did you did this time to piss him off?LOL I see that he is posting over on the TSF
Later
Dan

 

[Fish]

It takes over a case of beer to be able to hear the ping.
I am worried about Otto, its not like him to walk away
from good bickering material. Probably mad about the
Walt Galer racing chain thread. I have been throwing
good anti-electrolux jabs and not getting anything back
from him. Electrolux man is filling the void nicely though.
I would like to get them both to the Expo in Louisville
so they can both demo all the Huskies and Jonsereds
they want, I will hang around Miss Sweden as usual in my
overcoat and mirror shades. It is a shame Stihl no
longer attends, I miss the free beer.

 

[sedanman]

Ok guys I HAVE heard a 2 stroke ping. It wasn't a chainsaw, it was my Maico 250. The bike was making more power than usual and sounded different, then it ground itself to a halt. Turns out the crank seals were sucking air, the motor got lean, got hot, pinged ( I heard it but didn't identify it fast enough) then scored the piston. BTW the Maico was sorta left handed, shifter and kick starter on the "wrong" side.

 

[eyolf]

I used to hear pinging quite regularly on snowmobile engines...just before they made a loud "SCRRRIIITTTCH" sound, and locked up. Once in a while a guy could choke them down and save his engine, but not often. I used to run sleds without any cowlings over the engine just for that purpose...stuff my chopper in the carb bell to flood the engine with cold gas when it was locking up.

I've heard it on motorcycles, too. More often on warm days and when hill climbing, just before powering out. Yamahas seemed the worst, but all of them do it. Good reason to switch to four stroke hondas. I used to be able to dyno 40 hp regularly out of bored and stroked XL-350's, set up for flattrack racing. Beat the stuffing out of Yamaha TT500's.

Sorry for the side trip. I've never heard a modern chain saw ping or knock, but then most of them made in the last 20 years run pretty fast. maybe on a 6 cube saw, pulling a long bar through sappy pine. Probably also a death rattle, like the snowmobile thing.