Can I Run a 40:1 Two Stroke on 50:1 Premix?

The old Jacobsen 2-stroke engines specified 16:1 !!! I think some of the old Homelite engines did, too. Not only does it depend on the oil being used (syn vs. dino) but also the type of bearings used in the engine. The Jacobsen engine used plain bearings on both the crank and the rod, and plain bearings require much more oil to lubricate properly. Most, if not all, modern 2-stroke engines use ball and/or roller bearings and they can get away with much less oil.

freetown fred wrote:If I were to take everything I read as Gospel, I'd probably go broke trying to keep abreast of all the yearly " BETTER" products available. Hmmmm, are eggs good for me this year. I know whole milk isn't, but I've been drinking it for 66 yrs and those little see through motors on many parts counters that show viscosity effect??? if it works for you, that's what counts--I was just sayin I've never even seen 0-30 oil. I need to get off the hill more often I guess.

Eggs and milk are essentially the same now as they were then albeit we're adding a few more hormones and antibiotics to some of the pipelines Lubricating oils aren't. Essentially, petroleum based oils are separated out of the crude with a few modern chemical packages added. Synthetic oils come from petroleum based chemical products, not oils, that are chemically reacted/recombined to synthesize something that didn't exist before. Better living through chemistry - remember? They all work well, just some do their jobs better. I'm still using a '65 gravely and all the much older attachments that I've rounded up over the years. All still working as designed and only ever lubed with petroleum lubes but they're made a lot heavier than anything made today so there's a lot more to wear. New stuff is a lot lighter. New stuff I keep fed with new stuff

Stay on the hill, I sure would! Here's a pic from the lube stash to prove it does exist. Who'd a thunk it - 0 viscosity.

Outstanding, I've now seen it. Yes after 2 tours in Nam,& thanks to Dupont--I'm familiar with better living through chemistry. I did break down & buy a new Poulan 18" bar at Lowes & started useing the old school mix & she runs & starts one pull every time--not much longevity behind her But---we'll see--the old theory--break er in the way you're gonna run er.

VigIIPeaBurner wrote: Here's a pic from the lube stash to prove it does exist. Who'd a thunk it - 0 viscosity.

Shoot...they are running 0W-20 in a lot of new engines today, mostly for fuel efficiency reasons. However, there is a correlation between bearing clearance, rpm, and loading that dictate which viscosity will provide the best lubrication. It is a rather fine line, and thicker is most definitely NOT better. If the lubricant can maintain tight viscosity control over wide temperature extremes, the bearings can be more optimally designed to run with thinner lubricants and not give up longevity. A significant amount of energy is wasted through the hydrodynamic shearing forces in a plain bearing engine design, and that wastes fuel and heats up the oil. Go too thick on the viscosity and the oil can't flow through the bearing fast enough to remove the heat and you end up with overheated bearing shells, scoring, spun bearings, etc.

europachris wrote:The FS-36 still ran great, but one day I was trying to finish trimming and the head kept jamming up and wouldn't feed. I got so irritated with it I just bent the thing in half and stuffed it in the garbage can.

HAHAHA I know how that goes! Smitty does too! I bet you weren't breathing in that last second before you gave it what fer! I almost smashed my little Craftsman
leaf blower today, was trying to clear the gutters of the customer before the rain hit! It'll run all day but starts very hard when hot. It's gotta come apart. I have 2 of 'em, both not running now. I had to get the guy's backpack blower on and climb up on the roof off a step ladder.
Then he tells me his phone cord is too tight, after Ijust spent 4 days saving his ground floor carpets. hahahahha

freetown fred wrote:Yes after 2 tours in Nam,& thanks to Dupont--I'm familiar with better living through chemistry.

Fred, ya got any Agent Orange defoliant left? I want to give the neighbors lawn a treatment in the middle of the night.....

Dann757 wrote:Fred, ya got any Agent Orange defoliant left? I want to give the neighbors lawn a treatment in the middle of the night.....

Good heavens man! What have they done to deserve your wrath?

2 strokes are amazing if you take care of them. Give them the oil mix they want, the inconvenience of having one more gas can around is not worth the trouble of fixing what was not broke before you pushed your luck.

Thanks for the replies. I think I will take my chances. Freddy’s advice was good and it is what I would do if I were to do it over but this Weed Eater appeared here one day and I was bitching about why it is here and that it was in my way and to get rid of it. The wife then explains that her brother dropped it off and it was her parents before they passed and if I were to get it running for her that she would trim the yard for me. After that I saw the 40:1 on the cap and told her I didn’t have the proper gas oil mix for it hoping this would make her see that we have no use for this thing but she insists on wanting to use it. I honestly think it only has to work for one tank of gas, just long enough for her to decide that weed eating sucks, but if it quits for whatever reason during that one tank it will surely be my fault and most definitely because I put the wrong gas in it.

2001Sierra I see you point if this was a better machine like Shindaiwa, I know their two strokes specified a 40:1 mix but this is a low end POS that I paid nothing for, I just don’t want to be accused of ruining it if it failed immediately on the first tank of fuel. I’ll cross my fingers it can run an hour on 50:1.

[quote="freetown fred"]Outstanding, I've now seen it. Yes after 2 tours in Nam,& thanks to Viagra--I'm familiar with better living through chemistry. she runs & 'starts' one pull every time--not much longevity behind her But---we'll see--the old theory--break her in the way you're gonna run her.

R we still talking about 16 to 1, or are you now liking the 50 to one strokin'?
I can only imagine how hard you have to 'run er' out on the farm!

Hell, I don't know WN. Whatever a couple glugs comes out to. Yes, I run em all hard.

Hey wait a minute. How'd that Viagra get in there?? Is nothing sacred? [quote="whistlenut"][quote="freetown fred"]Outstanding, I've now seen it. Yes after 2 tours in Nam,& thanks to Viagra--I'm familiar with better living through chemistry. she runs & 'starts' one pull every time--not much longevity behind her But---we'll see--the old theory--break her in the way you're gonna run her.

R we still talking about 16 to 1, or are you now liking the 50 to one strokin'?
I can only imagine how hard you have to 'run er' out on the farm!

2001Sierra wrote:2 strokes are amazing if you take care of them.

I found this little gem while researching high-output alternators.

You may be old, but you can still 'pick up what I'm puttin' down'. Hugh Hefner said the magic 'V' is the best legally obtained l drug in his lifetime. Damned good thing you don't live in VT!!!!!!! I've asked Stoker Scott is he has 'Limmer' make those special boots for him......I've never seen them anywhere else.

I have found that 50 to 1 synthetic works in all 2 stroke engines. It isn't what we had back in the 50's, 60's and 70's.
Today's issue is the damned ethanol at 10% ruining the engines and attracting moisture. Freddy has a darn good suggestion that I have heard from other aviation folks. Not a good idea to have anything that attracts moisture when buzzing along at 10,000 feet. My brother has a few friends at the local airport that allow us to buy all we might need. $5.95/gallon, but 5 gallons lasts a long time unless you have an outdoor wood boiler.....then it will last a week, or 5 cords.

Anytime you want to turn off the rain water tap I'd be grateful, over an inch yesterday.....rain all day and the next couple days.

I've been running 50:1 or leaner in every 2-stroke I've owned in the past 20 years. Never had to rebuild one twice, if that tells you anything. No marketing hype here.

My dirt machines all used to get one bottle of Golden Spectro to 5 gallons of gas. One bottle = 12.3 oz. .. which comes out to 52:1. Ran that in my '87 Honda TRX250R for over 2 very hard years without even changing the spark plug. The day I sold it, it still started first kick & pulled the front wheels skyward in all 6 gears. I always mixed in 5 gallon batches, because I would go through 5 gallons in one weekend - that's how much riding I did back then. I can't even tell you how many 5 gallon cans I burned in that machine in 2 years - over 50 at least ( can't ride in 2' of snow with a rear wheel drive race quad ). Mostly full throttle, climbing the steepest sand hills in the pit, & a little trail riding mixed in.

The thing with premix is, the more oil you use, the LEANER it makes your fuel/air mixture. So you can actually seize an engine using TOO MUCH oil. Lots of people don't understand this. Lean fuel/air mixes run hotter & are more prone to detonation or pre-ignition - both deadly to 2-strokes no matter how much or what type of oil you use. With this knowledge you will never seize a 2-stroke with any oil/gas ratio. Oil displaces fuel.

So if you change to a richer oil/fuel mix, you need to add more fuel to correct. Turn those screws OUT. The opposite is true for leaner mixes. I find that my 2-strokes make the most power on the leanest possible oil/fuel mix.

I run Amsoil Dominator in my RD350 exclusively since I restored it. Do you think I would run that if synthetics weren't what they've been advertised to be? I don't have the dough to rebuild that thing, so I use the best there is. Lots of guys tear down their engines every year for re-ringing. I run mine for years & never touch the insides again in most cases. But I also can tell just by listening to one run if it needs to be richer or leaner.

Hard starting when hot = too rich on the low speed circuit - turn the screw in a bit ... but not so far that it goes BOOOOOOOG when you hit the throttle. If you need the choke to start it when it;s hot, then it's too lean. Turn the screw out ... but not so much that it starts to break up, or sound like a 4-stroke. You want that smooth, even buzzzzzzz. And also remember - the low speed circuit has nothing to do with wide open throttle, & vice versa. Actually the low speed circuit adds a small amount of fuel to wide open throttle because all circuits overlap, but it's insignificant, & can be compensated for by adjusting the high speed circuit last.

Was trying to do a little research on Amsoil Saber and Mobil 1 mx2t and found this article, good little test on a 2 cycle engine. http://www.geistware.com/rcmodeling/articles/oil_ ... /index.htm