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 Can you use motor oil instead of 2 cycle oil in a pinch?
yekimak  [Team Member]
5/20/2007 4:04:24 PM EDT
Just curious. I don't know if it would ever become a necessity to improvise in such a manner for anyone, but it would be good info to know JIC.
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twonami  [Team Member]
5/20/2007 4:05:24 PM EDT
tagged cause I'm curious too
odjoe  [Team Member]
5/20/2007 4:28:15 PM EDT
well when I was a kid and had a few 2smokes I use to mix motor oil once in a while no difference in wear in the long run .always changed the rings when needed bikes always keep on going not scientific but it worked
bill3rail  [Member]
5/21/2007 5:07:54 AM EDT
I have seen it done many times! It will smoke like a bitch, build up excess carbon, and foul plugs.

I would NOT recomend it, but in an emergency stiuation if you just had to run it, and could not wait, I would do it!

Just make sure that you clean all of the fuel out when you get the proper mix oil.

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UcB4uME  [Member]
5/21/2007 5:29:36 AM EDT
When I was a kid, we had a 13' Boston Whaler with a 40HP Evinrude. We ONLY used motor oil in it. It ran just fine for years. With that said, I wouldn't think of doing it today unless it were an emergency.
KB_TX  [Team Member]
5/21/2007 5:42:44 AM EDT
Standard motor oil will eventually score the cylinders of your 2 cycle engine and cause loss of compression. In a pinch, maybe, long term will cause excessive wear...
GeorgiaBII  [Member]
5/21/2007 5:56:56 AM EDT
You can do it and no it won't score the walls..

The trick is to mix it at 75% of the recommended mixture for 2cycle oil. That reduces the fouling and carbon buildup.

Still smokes like a bitch but it's very useable.
unclemoak  [Member]
5/21/2007 6:08:24 AM EDT
It is doable. In an old manual for a Stihl chainsaw ( and by old I mean made in West Germany old) I have read that you can use motor oil in place of two cycle old, you just need to use a lot more motor oil than you would two cycle. I'm not sure of the correct ratio, but I do remember that it is significantly more than two cycle.
JakeThePimp  [Member]
5/21/2007 8:06:36 AM EDT
Yes. It will smoke more. We did a 600 single day snowmobile tirp and one of the guys ran 10w-30 for the whole day, no troubles.

TheOtherDave  [Team Member]
5/21/2007 8:26:03 AM EDT
I wouldn't do it in any motor I cared about or needed to count on. 2-cycle oil is very different to motor oil, they are made for two entirely different applications.
KB_TX  [Team Member]
5/21/2007 10:17:00 AM EDT

Originally Posted By GeorgiaBII:
You can do it and no it won't score the walls..

The trick is to mix it at 75% of the recommended mixture for 2cycle oil. That reduces the fouling and carbon buildup.

Still smokes like a bitch but it's very useable.

You are quite the expert I'm sure...

The basic viscosity of two cycle oil is around 20W. However do not substitue a regular motor oil for a two cycle one.
There are special additives and base oil types used in two cycle that are not really important in motor (or lube) oils.
If you use anything but two cycle in your engine you stand a good chance of a literal "Meltdown".
For a real in depth explanation go here.
0_Windage  [Member]
5/27/2007 7:45:17 PM EDT
No oil expert here, but I understand that regular 4 cycle motor oils typically contain 1)detergents and 2) parafin-over certain viscosities. 2 cycle oils are meant to be combusted as well as lubricate so they don't contain any additives that might impede the combustion process.

I guess the detergent and parafin would eventually foul the spark plug or gum up the rings, whatever but in a pinch, if it is all I had I would consider using it esp. if an emergency.

A better choice if available might be a 4 cycle oil that says it is non-detergent type and not over SAE30 weight . I have heard that anything over 30 weight has parafins to increase the viscosity. Parafin is what leaves the sludge / thick goo if you go too long on oil changes.

As a kid, we had an old Yamaha 250cc motorcycle and bought the cheapest crap we could run..which happened to be 4cycle non-detergent SAE ran for years. I forget the mixture ratio but these newer 2 cycles run pretty lean on oil and probably higher temps - so be careful.

trwoprod  [Team Member]
5/27/2007 9:06:34 PM EDT
I would urge you to look at the better synthetic two-stroke oils. For many applications, you can run them safely at 100:1 (probably not a loaded snowmobile, but other applications), and that will make a case or two of oil last a long, long, long time and makes carrying an extra bottle on trips easy because it will get you back home.
fxntime  [Team Member]
5/27/2007 9:17:04 PM EDT
Old homelite chainsaw I had used 30 wieght 4 stroke oil but when I say old I mean it was a belt drive beastie that weighed about 40 pounds and had a chain whose links were 3 x the size of a new one. Smoked but lasted for years, quit using it because I could not find another chain that would work.

Many OLDER 2 strokes could use "4" stroke oil, the mixtures were also around 16 to 1.

2 stroke oil is ashless and is designed to be burnt leaving few deposits in the combustion chamber, it is far superior to 30 weight 4 stroke stuff but that won't kill your engine if you HAVE to use it in a pinch as long as it is mixed properly. You do get what you pay for in 2 stroke oil, a few bucks over a season for better stuff is a small price to pay.

BTW I still have a Lawn Boy from the 60s/early 70 that uses 30 weight motor oil per the directions on the tank, still runs too. You have to clean the expansion chamber once a season for maintainance.
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