Question on 2-Cycle Engines (Gas / Oil Mixtures)

[buckeye95]

All,

Debated whether to post this question in Tool Talk or here, but given it is not WW related, I thought this might be the best place.

I currently have a Lawn Boy mower which uses a 32:1 gas / oil mixture and a weedeater that uses a 40:1 mix. I was at the outdoor power dealer the other day asking about oil. He stated that most new stuff has moved to 50:1. When I told him I did not like having separate can and mixtures for each tool, he stated that they run everything on 50:1. He told me that they run all tools (even the older tools they repair and service) with 50:1 mixtures using Echo oil. He said it did not matter if the tool is supposed to use 32:1 or 40:1, 50:1 with Echo oil will work.

Is that true ? I obviously do not want to damage or prematurely wear my mower or trimmer. Normally I would not believe something like this, but this is a big outdoor power shop that carries lots of big brands (Stihl, etc.) Is this guy correct? Can I use 50:1 on everything?

Thanks in advance.

Pete

[Daryl]

I would stick with what has not caused any problems. You can probably get by using the 32/1 oil in your weedeater too, just see how much smoke it makes.

[sparkeyjames]

Just use the 40:1 then your about in the middle. I have stihl chainsaw that requires 50:1 and a weed whacker and snowblower that use 40:1. I use one gas can for all of them at 40:1. What little extra oil is in the mix is not going to effect performance to any noticeable degree.

You can get 2 cycle oil packaged in nifty bottles with a measure chamber built into them. I find them quit handy.

[Tom Slick]

From what I have gathered it depends alot on the oil. When that Lawn Boy was built 2-cycle oils weren't as good as they are now. I'd run both at 40:1 and not worry about it. Almost everything now specs 50:1.

Side note: Amsoil makes a 100:1 oil for power equipment and warranties your engine against damage. I don't know if I'd trust it but I have not read of one instance of a person burning up an otherwise healthy engine on it.

[LCHIEN]

i recall this question has come up before and had extensive replies. Try searching for combinations of 2-stroke and oil and gas and mixture. I know just 2-stoke comes up with several hits.

[Tequila]

I also just use one tank of 40:1 for all my 2 cycle yard tools.

[JimD]

A little heavy on oil risks fouling the plug and perhaps plugging the muffler (or spark arrester) but not wearing out the motor prematurely. I generally tend to go a little heavy (like use 32:1 in everything in your case).

Coincidentally, I was testing my boat motor this morning. It is an old Evinrude 70hp with a fancy fuel/oil pump that mixes the oil as it pumps it to the 3 carberators. It ran well this morning but very poorly the time before that. I took the carberators apart but didn't see anything wrong so I thought maybe it was the fancy fuel/oil pump. It is $320 to replace so I was planning to just use mixed gas. I took an extra 6 gallon tank mixed at 50:1 (the heaviest the fancy pump mixes, under some circumstances it is supposed to be 150:1). It ran well on the mixed gas but, just to check, I also tried the straight gas from the built in tank - still going through the fancy pump with oil connected. It also ran well that way! That seems to mean I was at about 25:1 when I was on the pre-mixed gas. Much heavier than required. Ran just as well as at an apparent 50:1. Top speed of the boat was the same, may have idled a little better with the straight gas but it would idle with the pre-mix. Slow speed was also fine either way.

Long way of saying my experience is that it is not very sensitive. Extra may foul your plug prematurely but otherwise should be safe. Prematurely probably means 2-3 years instead of 4-5 years.

I also use high grade 2 cycle oil made for boats in my other 2 cycle engines. You can still get Johnson/Evinrude oil but Mercury is probably at least as good and is more readily available. I think mine is Lubrimatic. There are grades from standardized testing and I think as long as it passes the same tests, the "off" brands are fine. I also have used the 50:1 from my boat gas (I mix a little high, however) in my yard tools. I've never had an issue. My chain saw is over a decade old (but doesn't get used a lot). I buy pints of 2 cycle oil to get the scale in the side and table on the back so I do not have to exercise my brain figuring out how much to add when I get gas. I am still using a 3 gallon jug I bought several years ago, I just refill the little bottles from it. For yard work, the pints would be a good deal (I paid less than $2/pint last week for a couple).

Jim

[JeffG78]

Oil quality is much more important than mixture rate. I have been around 2-strokes for close to 30 years and have always had one pre-mix can for everything no matter what the various engines called for. Every dirt bike I've owned has called for a 32:1 mixture, but they base that on dino oil. I have always run synthetic oil in my bikes at around 45:1. Usually the synthetic oils can be safely mixed at well over 50:1. The most important thing is to always use the same brand of oil and the same mixture in a given engine. Don't switch between oil brands or types (dino/synthetic). You can do it once to change everything over, but don't go back and forth. Also, if you do switch, DON'T MIX them. Completely drain the tank and carb before switching over. If you find that you are oil fouling plugs, then either change the plug brand/heat range, or adjust the carb settings. A slightly hotter plug will do a better job of resisting oil buildup. White residue on a plug indicates a lean mixture or a plug that is too hot and a colder plug should be used.

One thing most people don't realize is that more oil will make the engine run LEANER, not richer. Air/fuel ratio is the ratio of air to fuel. More oil means that there is less fuel in a given volume of pre-mix.

Now that I no longer ride dirt, I went back to cheaper dino oil. I use Homelite oil at 32:1 in the three or four 2-stroke implements I own even though they all call for different mix rates. After ten years, they still all run great.

[lrogers]

Most of the guys that fly r/c gassers, both planes and helos, will use full syntheic oil mixed 40:1 for break in and then go to 50:1. From the forums, it seems Amsoil and Yamalube are the preferred oils.

[RAV2]

Seems like a lot of replies in different directions here.

I too had a 32:1 (old small rototiller), 40:1 (weed wacker and chain saw), and bought a new Redmax blower (50:1 I think).

I called Redmax and asked about using 40:1 (I did not care about the old rototiller).

Redmax said that 50:1 allowed them to meet California emisisons and that 40:1 - though making more smoke - would be fine and not void a warranty.

Regarding engine wear, I would never run a motor with less lubricant than required by the manufacturer for fear of getting excessive wear.

As far as 2 cycle oil goes, you need the appropriate grade oil (API certified I think). I found the 1 gal jug at Walmart had the proper certs and was very inexpensive.

Find a motorcycle shop and get the funnel with the graduations on the side for different mixtures and tank sizes. I find it an invaluable addition to my shed.

[buckeye95]

Thanks for all the replies. This has helped me get this straight.

Regards,

Pete

[wbsettle]

Just to add my .02. Being in a similar boat...32:1 weed eater and 40:1 leaf blower, Lowes/HD/etc. carry several synthetic oil brands that claim to be compatible with 32/40/50:1 when mixed with 1 gallon of gas. Going on 4 years of sharing one formula using these "universal" additives and both engines seem to be running fine.

The universals I've purchased are in 2.6oz bottles, which works out to 50:1 with one gallon of gas. The $100ish Ryobi weedeater had at least 4 seasons on true 32:1 before the blower joined the fleet requiring the switch to the universal oil. Can't tell it runs any different at 50:1...no extra smoking, hard starting, or reduced power and I'm sure I've used the chainsaw (pole pruner) and hedge trimmer attachments to cut larger material than "recommended".

As always, YMMV.

-Brent