OOps 2hp Elgin not fully cured, gas to oil? need help

[Texwing]

OK, the little 1958? 2hp elgin that finally started running well was doing so on a 15 to 1 mix of Stihl Chainsaw Oil and our local regular gas with 10% ethanol.
It was doing so well that I mixed gallon of gas with sears 2 stroke air cooled oil at 16 to 1. The sears oil might have been 10 years old but never opened, foil seal intact. I am very precisely measuring the gas.
Test spin on the lake and after 10 or 15 minutes at full throttle, power starts dropping off, motor runs slower, finally dies, wont restart-and is much harder to turn over.
Back to shop, lots of spark, I cool it down with air, mix another batch of oil with the Stihl oil and gas at 15 to 1. Now, it takes a long time and alot of pulling, but finally it starts, barely runs for a while, and at last takes off strong in the test tank. Back to the lake, runs well at full throttle for a long time, no more issues.
All this means something, but I am not sure what-it seems borderline that a different oil at a bit higher ratio makes a difference, but it does. Carbon in the head? should I go to a 14 to 1 mix? I am not sure how much oil I can add before fouling plugs, and what is wise, and what I should do for this little motor-as always, your help is appreciated.

 

[nightingalemoon]

Re: OOps 2hp Elgin not fully cured, gas to oil? need help

I think your sears oil was bad, and it either overheated your engine, or gummed up your cylinder. Like gas, oil can go bad. It can sour, this makes it smell rancid and it loses all viscosity becoming sticky. Oil can also thicken at the molecular level, causing it to burn slower because the molecules are in big clumps. The same thing happens to fuel when it sits around too long. I know they make fuel stabilizer that slows or stops the molecular recombination process, but I dont know if theres a way to treat oil in a similar way.

My advice is to throw away the old sears oil and continue doing what worked before, use stihl oil at 15-1 untill all the sears oil is burnt out of it. Then, later if you want to increase your fuel ratio do it with the same oil you are used to using. Just remember, less oil equals more heat, and less lubrication.

 

[tmcalavy]

Re: OOps 2hp Elgin not fully cured, gas to oil? need help

A 58 anything would have come with a factory recommendation of 16:1 or 24:1 using straight 30W oil. Try some TCW-3 marine two-stroke oil at these mixtures. I've never run anything but TCW-3 so can't tell you if using chainsaw oil makes a difference.

 

[Texwing]

Re: OOps 2hp Elgin not fully cured, gas to oil? need help

Ok, I did not know oil had a real shelf life, but I will take no more chances. I used the Sears oil since it was specifically for air cooled engines and had the tc designation. All stihl engines are air cooled so I also figured their premium 2 stroke oil would be good, and it seems to be doing OK, at least at 15 to 1 ratio. The elgin still has the sticker for 16 to 1 ration of straight 30 or 40 weight engine oil. I would buy the best stuff I could find if I knew what I was looking for and where to go, I bought some Penzoil synthetic marine 2 stroke but no where did it say anything about air cooled engines so I did not use.
Also still wondering, does an engine with lots of carbon exhibit this kind of behavior? would running premium gas provide any value? thanks again for all the help.

 

[nightingalemoon]

Re: OOps 2hp Elgin not fully cured, gas to oil? need help

Yes, almost all petroleum products have a shelf life. Different ones last different amounts of time, and environment makes a significant difference - temperature mainly. Think about how many times that sears oil could have got cold in the winter and hot in the summer...

Stihl is a premium chainsaw, I have personally used them professionaly, and Im sure the oil is good for anything that calls for that type of product. To be honest though, you should be able to use ANY similar air cooled 2 stroke oil in the same 16:1 mix for exactly the same results.

I have also used ams-oil synthetics and found them to recomend too light of a mix, which results in a hot fuel. I dont know if other synthetics reccomend changing mixture, but I would be wary of that if you try any.

Using premium gas will usually result in a much higher running temperature. Ive seen premium gas accientally added to chainsaws, and even with the proper oil mix the premium fuel caused the muffler to glow it got so hot. Dont use it.

If you decide to use regular motor oil for the mix make sure you get non-detergent oil (thats all they had back then), and make sure theres not a numerical prefix, in other words use (Non-Detergent) ND40 and not 10W 40. The viscosities of the other oils are different, so use what they reccomended.

There are threads here describing a de-carboning process using a product called seafoam (or something like that). I dont know anything about it, but Im sure it was a good suggestion. Try that if you want. Also, I have seen a little water sprayed from a mister into the carb at high idle make internal carbon break off in an old V-8. Im not suggesting you try that, since a 2-stroke operates differently and water may go where you dont want it. If you do try it, just make sure you run your engine long enough to evaporate any water that might have been left behind.

Last, I doubt if carbon is your problem. If it was, changing oils wouldnt have affected it so much.

If your motor isnt smoking too much at 15:1 then stay with that range. 16:1 is essentially the same mixture, and might give you a tiny bit more power (1/16th more to be exact) and thats the mix your motor calls for.

Im still caught on the sticker asking for a 16:1 mix of regular motor oil. Ive never heard of this before. ND40 weight (ND = Non Detergent) motor oil is a LOT heavier than any air cooled mixing oil. I dont know what effect that has after its mixed, but if I were you I'd try using some ND 40 and see what happens. It may be that it will lubricate better, run cooler, and with more power. Maybe not. But if thats what it calls for it surely couldnt hurt. You can get ND40 at most gas stations and all auto parts stores. If your motor runs hotter on this new mix then dont use it. If it runs cooler and dosent lose power then use it. This oil may not burn as easily as mixing oil, which might leave a bad smell, a lot of smoke, or a film of pollution on the water. If thats the case, you might not want to use it.


Good Luck

 

[Texwing]

Re: OOps 2hp Elgin not fully cured, gas to oil? need help

yes, the factory sticker on the little elgin recommends "sae 30 or 40 weight oil, and 24 years ago when I was fooling with this same engine I tried some straight 30 weight and it seemed to do OK, although I used 30 weight non detergent oil. I have read things recently that suggested the modern 2 stroke oils are the better bet, but to use 2 stroke oil for air cooled engines in this air cooled Elgin.

I found some "Penzoil Premium Plus synthetic blend" oil with the TC-W3 rating, but I am not sure this is the air cooled stuff, but I am thinking the synthetic aspect would give it really good high temperature film strength. I will get the best stuff available, i just dont know what it is. thanks for the info.

 

[F_R]

Re: OOps 2hp Elgin not fully cured, gas to oil? need help

yes, the factory sticker on the little elgin recommends "sae 30 or 40 weight oil, and 24 years ago when I was fooling with this same engine I tried some straight 30 weight and it seemed to do OK, although I used 30 weight non detergent oil. I have read things recently that suggested the modern 2 stroke oils are the better bet, but to use 2 stroke oil for air cooled engines in this air cooled Elgin.

I found some "Penzoil Premium Plus synthetic blend" oil with the TC-W3 rating, but I am not sure this is the air cooled stuff, but I am thinking the synthetic aspect would give it really good high temperature film strength. I will get the best stuff available, i just dont know what it is. thanks for the info.

If you want to do a good read on oil, try this tech article from Sea-Doo:
http://www.sea-doo.net/techarticles/oil/oil.htm