Oil mixtures and thoughts

50:1 is an epa thing. When Stihl started the production of the more modern saws very similar to the normal saws today not the auto tune ones but normal saws they recommend 40:1. Then whatever year some new emissions standard ratcheted down on OPE they went to a 50:1 recommendation. Literally same model number saws and exact same Stihl oil but one year it's now 50:1 and the previous year it was 40:1.

Lots of Chinese stuff you see that probably cares nothing about regulation etc still says 40:1 on it. Last thing I got was a pole saw, it's been like 3-4 years since I got it but it was like Remington brand off Amazon and it said 40:1 on it.

 

Even old saws, boats, whatever 2stroke engine I run at 50:1 with modern 2 stroke oil. Oil now is sooooooo much better than it was back in the day.

 

I would be willing to put money on that answer will be to run it at 50:1 with modern quality two stroke oils.

I remember back even in the 50:1 recommendation days reading the Stihl manual...I think I remember it when I bought my ms390 like 16 years or so ago something about if you didn't use Stihl brand oil to double up the oil mix ratio , so run it at 25:1 if you used say super tech or Lucas oil.

 

Yep Evinrude decades ago said to run all their engines at 50:1...but it was around the EPA times that recommendation came. When I premixed my fuel for my outboards I would always run 40:1. I still have the VRO connected on my 60hp Evinrude so it mixes at whatever ratio it does. It's leaner ant idle and richer at WOT. I'm not 100% sold on you have to disconnect them cause they will lean out and burn up your engine. My understanding of them is when they fail they default and dump oil into the system and over oil not the opposite. Now if I have trouble out of it I will 100% disconnect it and go with a normal $30-50 fuel pump off the regular or special models and premix my fuel. But that's cause I don't want to spend $350 or more on a VRO prump.

 

Scotty Overkill runs some old Pioneers. What do you use Scott?

 

I knew it was in there. I remembered reading it for a saw my uncle either bought in the late 90s or on the saw I bought in 2004.

 

I bought a new Troy Bilt saw to experiment on this year. 40:1 right on the tank. It's an MTD product like Remington and Craftsman sold at places like lowes ect. I had also purchased a new Remington leaf blower for experimenting on and it too was 40:1. Made in Mexico that one was.

 

I agree 100%. Look at Leon's chainsaw parts and repair on YouTube. He is a vintage saw collector and runs Saber at 80:1 in all of them. He has a video on it where he specifically addresses this subject.

Would I run 80:1? Not in anything outside of my oil tests lol. More oil is more power if the carb can flow the mix. Proven over and over with bikes in dyno cells. 15:1 - 18:1 made the most power and left the least amount of carbon. The ability to change jets in bikes makes this rich of an oil / fuel ratio possible. Unfortunately, with saws and pretty much all 2 stroke ope, we are limited to the adjustment screws and once you run out of adjustment you are done. Of course you can drill out the jets but I'm not doing that just to run more oil. I'll either change the mix ratio or brand. I just had this happen in the Makita 3601 I ported for myself. On 32:1 Castrol GO full mineral oil that I use for break-in, I had the High needle turned out so far it was getting loose and it still wasn't rich enough. I switched it to my normal 25:1 full synthetic oil mix and it immediately was too rich and dropped 500 rpm before retuning. Other oils can have this effect on ope as well. What ratio it happens at depends on the viscosity of the oil and how big the carb jets are. Generally, a larger CC saw should be able to get away with a ratio that a smaller saw might not if they are using the same oil mix.

After all this rambling I tell anyone who asks me to run 32:1 - 40:1 and give them a few suggestions of oils I know from testing will protect better than most.

 

Don't think I would go to that extreme. Why? I only see that as a benefit if your these lawn care guys trying to save every penny to make the bottom line better. Sure oil is better, they say you can run that ratio without trouble, I know there many commercial guys that do and Amsoil says it's fine as well. A burnt saw doesn't payoff for the oil you saved but I have seen enough commercial guys who are some of the hardest on equipment say their stuff is fine at that ratio and lasts just as long. Good for them and I believe them but I don't see the point of it for vintage, hard to replace stuff that you burn so little fuel through what does saving a dollar a gallon of oil make. The oil at 40:1 hurts nothing even if it's overkill.

 

Despite what I've seen from my extreme lean oil tests, there is no way id run leaner than 50:1 and I've only ran one gallon of 50:1 mix in my life. That was Red Armor in my leaf blower.

 

Makes sense...EPA wants as little oil as possible in the air, and even more so the water...and as long as their engines make it past warranty period (plus a little hopefully) OEM doesn't care what the mixture does to the engine long term...heck, I'm sure they have no problems selling you parts!

Many/most of those guys replace their equipment every year or 3 too...so as long as it makes it that long, they are good with it. Would it last even longer running more oil, yup. But most of us here don't put enough hours on to find out where that point is...

 

Oddly enough? the oils that claimed 70-100:1 ratios did well in my lean ratio testing. Saber, Blue marble and Opti 2.

 

That’s a deep rabbit hole with many different paths to be followed lol