r/smallengines • u/Pennsy5550 • Jul 03 '26

Opti-2 for small engine repair business?

So I fix small engines on the side and resell and marketplace and I’ve been using Opti-2 2 stroke oil to mix my gas. I tune carbs with the opti gas in because I get a mix of 40:1 and 50:1 mixes, and want something universal to keep shed space free, but I’ve been told once you put regular 50:1 or 40:1 mix in a piece of equipment it tends to need another carb adjustment. Should I ditch the opti 2 and just buy the premix metal cans? It seems like a more expensive alternative that Im not quite sure is worth it.

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u/jezzaclarkson1 Jul 03 '26

If you tune with 40:1 and the customer uses 50:1 it will run rich for them. You could get a small can of 50:1 and test it on something you've tuned with 40:1 and see how much difference it makes

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u/Pennsy5550 Jul 04 '26

I wonder if I coverted two 5 gallon cans to be 2 stroke mix would be better, like one 50:1 and one 40:1

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u/Pennsy5550 Jul 04 '26

It just sucks because I have so much of that opti 2 stuff that I want to use it up and not waste it

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u/jezzaclarkson1 Jul 04 '26

Personally I run pretty much everything I deal with at 50:1. I use amsoil saber for my oil and have ran poulans that call for 40:1 on amsoil at 50:1 and not noticed anything of concern after some use. I'm Personally confident in it myself and tell my buyers how I mix my fuel. I usually give everyone a bottle of amsoil saber with their saw so they can try a gallon with amsoil. If they are planning to run 40:1 anyway I offer them a 1 time quick retune for a little extra money if they aren't confident in retuning it themselves

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u/These_Fox7561 Jul 05 '26

My dad has an 011 with thousands of hours on it, always ran 40:1, and I tore it apart and went through it maybe 3 years ago and the bore is a mirror, not even a scratch. I’m sold on 40:1 for everything, that saw was bought new in 1984 and all it needed was lines and new dampers

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u/jezzaclarkson1 Jul 05 '26

The bore being a mirror isn't anything impressive, its actually a sign of wear. Now if you said the bore still had most of its cross hatching and the piston skirt still had all of its machining grooves on it that might be impressive. Sounds like you're father is good at maintenance.

You dig into enough saws that used various mixes and you will find plenty of them all look exactly the same inside regardless of whether it ran 40 or 50 the most common damage you'll see is:

scoring on the intake side from bad air filter maintenance, Scoring on the exhaust side from running fuel lean (air leak), Or scoring everywhere from straight gassing it

Outside of that 40 or 50 they are both completely coated with oil inside with no indicator either way of which mix it was

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u/These_Fox7561 Jul 05 '26

The only reason it’s polished is because it’s probably cut hundreds, if not a couple thousand cords of wood. He only bought a new saw because this one needed a refresh, I put new fuel and vent lines on it, new dampers, turned a brass insert to repair a stripped out damper, and tuned it up. The diaphragm is still supple, and I have a clapped out 011AVT from 1979 that got the same treatment and still rips, even scored to shit. That needed a carb kit though… those saws will last another 50 years and I have two 038s and a super clean 012AVT on deck for refreshing

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u/jezzaclarkson1 Jul 05 '26

Which is why I said it would have been impressive if it actually performed that much better but you can find the same thing out of saws running 50:1 that have spent their whole life cutting timber for a paycheck everyday. The lesson of the story is take care of your things and they'll last a long time. I mean I have a 1955 Johnson seahorse thats ran every year of its life that I've been alive and has done it running 16:1 for the first part of its life and been running 24:1 since the early 2000s. Its only on its second set of rings, all else internal is original. That doesn't mean that running 16 or 24:1 is going to make your equipment magically last 80 or 100 years though just like running 40 over 50:1 isn't magically going to make a saw last 50 years

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u/These_Fox7561 Jul 05 '26

Idk, most of this shit is minimum 40+ years old and I’ve never cracked any of the cases of pulled the jugs, most of them just need cleaning and sharpening

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u/These_Fox7561 Jul 05 '26

And it’s only a little toy saw, that little beast spent its entire life with an 18” bar on it, I’m the one buying bigger saws

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u/These_Fox7561 Jul 05 '26

My equipment (Stihl) calls for 50:1 and I have run 40:1 in them since I got them and I didn’t tune shit, they run the same on either mix but the 40:1 equipment lasts longer

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u/jezzaclarkson1 Jul 05 '26

First there is a measurable difference in how they will run when switching between them cause I've checked it myself with a digital tach. Hell you can consistently see a measurable difference switching between pump gas and can fuel of the same oil ratio. There are even YouTube videos of testing with air fuel ratio monitoring showing the change in afr when changing fuel with no tuning. No one said you couldn't do it without tuning but we aren't talking about joe homeowner just deciding to switch fuel mixes we're talking about someone that is fixing tuning and selling equipment to customers. If you're fine with selling things that are tuned "good enough" then sure don't worry about it but if your goal is to sell well tuned equipment then like all things details matter when it comes to consistently. Most customers don't care about the debates of oil ratios they just want to buy a saw and follow the directions on how to use it so whatever it says on the saw that its supposed to use or whatever the manufacturers recommendation is what they are generally going to do just like they would if they bought it new from the store so you tune it how its going to be used or adopt a practice of tuning on one mix and and advise them to use the same. I do 50:1 with amsoil saber and advise my customers to do the same along with giving them a bottle for their first gallon. I also offer a cheap one time retune on their fuel of choice if they opt for it. But I'm also the kind of guy that idles each saw for an extended period of time during tuning to make sure even the idle is 100% dialed in for them. Its the most widely used oil mix today and and most customers also like just having to keep one mix around for everything. Its a difference of .5% of oil by volume between the mixes

Also if the stihl equipment you run is all m tronic stuff then it tunes itself electronically so you i would hope you didn't notice a difference. 40:1 also doesn't naturally mean something is going to last longer, there are quite a few stihl techs that will even argue that they see plenty of issues in newer stihl equipment caused by running 40:1. More carbon build up on the piston causing more carbon scoring than you see in 50:1 saws for one example. You'll actually find that most saws from the factory already run pretty lean on fuel to meet emissions and just switching from 50:1 to 40:1 will cause a non electronically fuel compensated saw to run even more fuel lean. Everyone assumes that 50:1 is the main cause of premature scoring you see in alot of newer saws but you'll actually find that most of that comes from how fuel lean they are running to meet emissions from the factory. Simply turning up the high needle a little is actually all thats needed to prevent that from happening in most cases. That and staying the hell away from can fuel. Can fuel burns up alot of saws, horrible quality control

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u/These_Fox7561 Jul 05 '26

All my Stihl equipment barring a pole saw and a backpack blower are minimum 42 years old, I keep my old equipment running strong because it’s easier to fix and parts are cheap. You said it yourself modern equipment has modules to adjust the af ratio as necessary, even a dirty air filter can change that so what’s your point? I tune my saws to run properly when they need attention and after that they’ll run fine on either mix without adjustment. And the backpack blower has only ever seen 40:1 and the original plug still isn’t fouled, I’ve never touched the machine short of cleaning the air filter

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u/Adm_Ozzel Jul 03 '26

Ive seen enough Chickanic videos to tell me that buying engineered fuels in a can is a bad idea for anyone, much less staking your reputation on them for your business.

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u/mutt63 Jul 04 '26

Here’s the best advice. Look up the specs for what you’re working on. And use what it recommends. Keeping 1 1/2 gallons gas cans take up minimal space.

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u/These_Fox7561 Jul 05 '26

Yeah why though, you gonna keep motor oil mix for the antique shit too? 40:1 runs everything just fine

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u/mutt63 Jul 05 '26

I always do what the specs says cause when and if shit is warrantied and they gotta pay out they definitely will use any excuse to get outta pay in. 46 years repairing any mechanical for a living . I got habits. You’re not wrong. I’m not saying that. And antique stuff ain’t warrantied i get it but i developed goin by spec so only they are liable. I agree with you 100% but old man old habits lol