Gas/Oil Mixture

[Rockbadchild]

Oils have changed over the years also. So a Lawn Mower, Air Cooler, Hot Running, Small Engine, I would run a little Heavier than 50:1, maybe 40:1 or so. But Air Cooled Oil, not Outboard Oil that burns off at lower temps

interesting, i always wonder what was the difference with outboard mix oil … let’s say if someone is in a pickle and only has that just mix it richer in oil ?

 

[RandyT]

I follow the manufacturer's recommendations... for chainsaws 50:1. Hopefully they know what they are doing.
Somebody on this site has explained that too much oil will lean out the engine. I don't understand why, but it made sense when I read it.

The difference between a 50:1 and a 40:1 mix is negligeble. But lets break it down by oz of fuel mixture. An oz of 50:1 contains .0199 oz of oil and .9801 oz of gas based on a 128+2.6 oz complete mix. An oz of 40:1 contains .0243 oz of oil and .9757 oz of gas based on a 128+3.2 complete mix

So a carb that is calibrated for 50:1 will be set for .9801/.0199 mixture but if you use 40:1 the engine will only be receiving a .9757/.0243 mixture. So the lower amount of metered gas per engine cycle will result in a leaner fuel mixture.

As a side note the older Poulan Pro saws ran a 40:1 but the new saws are 50:1 so to compensate Poulan has come out with their own version of a premix gas like everybody is selling now. So how do you explain a multi-mix gas such as

But the can says for use in 40:1 products. So it sounds like Poulan is recommending the use of a 40:1 mix in their 50:1 products.

 

[Rockbadchild]

what is the carb calibration ? isn’t none electronic carb calibration only air vs fuel ration more oil in fuel = more oil in engin.

nvm it’s late … more oil in fuel = less fuel with the same amount of air = leaner … to run richer in oil/gas ration one would also need to adjust the carb air / gas ration.

 

[Cycledude]

Been using 50-1 since the 70’s in every 2 stroke engine I ever owned. Seems kind of amusing when folks claim that the manufacturer recommendation's of 50-1 isn’t enough and will ruin the engine.

 

[xyz123]

I run everything on Efree 89 and 40:1. Use JASO FD rated oil IMHO.
VPracing oil.
It's my equipment and my choice.

I wont run EPA ratio's they want you to run or what dealers been told to tell you to run. They dont care they are in the market to sell you more ope.

 

[NibbanaFarm]

nvm it’s late … more oil in fuel = less fuel with the same amount of air = leaner … to run richer in oil/gas ration one would also need to adjust the carb air / gas ration.

I have to tune all of mine occasionally. Husq chainsaw and hedge cutter, and Echo trimmer. I tune them by ear. I don't recall ever having to tune that old Lawn Boy mower though. All I remember ever doing to it was cleaning the air cleaner and reoiling it.