White Gas

[Markus]

Dogboy: Amoco or not, any pump gasoline should work for those applications.

[Markus]

Superdave, in a 2-stroke, it is not the valves that will burn. What will go first is the piston top edge on the exhaust side.

[sho305]

I thought in the old days white gas was cleaner, lead-free, and thus lower octane but stored longer. Though I also thought I read naptha can be an octane booster?

[Doubledog]

Originally posted by Markus
What will go first is the piston top on the exhaust side.

Why is that?

[Markus]

Because that is where it gets the hottest and where there is the most knocking.

[sho305]

Exhaust blows over the piston edge there and out the port every stroke, and that spot gets little cooling like the rest from intake/transfer ports. It only really gets cooling from the bottom of the piston. Every one I have seen run too lean or hipo and burned piston was melted there. That is one reason a pipe can work better on a 2 stroke, because it can pull fresh fuel/air out the exhaust port and then shove it back in to help cool that spot. Of course it only works at X rpm range for a standard pipe so not on an OB. This is a problem they are working on with DI motors where there is no fuel to cool the piston until the last moment so it runs hotter, or so I have heard. Some old hipo motors let some fresh mixture out the port to cool it, and out the exhaust.

[Doubledog]

You talk about burning the piston. What oil ratio's are you using? I run a heavy oil mix... 8oz - 1 gallon in these little engines. Outboard guys usually run what? 4-1 ?

[sho305]

I've seen the same melted piston on 20:1 sleds and bikes to 50:1 in outboards. Of course with jetted carbs you can run it leaner with more oil if you don't change them. Not sure it makes a big difference though if your mix is a little off.

[RUDERIOT]

is there more heat produced by burning an ounce of gasoline or an ounce of oil [ 20 wt or so] ???? THINK about it !!!!

[sho305]

Sure there is more btu in oil, but only the military runs diesel OBs and they are slower last I heard. It is harder to make oil explode in a motor and burn clean. That is why most every good diesel has a turbo on it now for more air, but they still run lower rpms and weigh a lot more. Pound for pound I think old crappy #2 fuel oil has the most btu of all, but not sure about motor oil as it is not often considered a fuel. I know it burns in my barn furnace ok once you get it started Cold starting sucks. I have a book here someplace that tells btu for fuels.

In my little force I run 45:1 mostly as I run it on the redline most of the time; instead of 50:1 it calls for. I ran 32:1+(maybe 25:1?) in a tankfull to test and it went slower for whatever that was worth. It only smoked more on starting or extended idle. I put a normal tank in and ran it a little then checked the plugs and they were very black with carbon, I think from the oil. Then again I am sure it is jetted/etc for 50:1.

[Markus]

Doubledog wrote:

You talk about burning the piston.

Exactly. On an 2-stroke, you burn the piston on the exhaust side. On a 4-stroke, you burn the exhaust valve. Similar phenomenom.

What oil ratio's are you using? I run a heavy oil mix... 8oz - 1 gallon in these little engines. Outboard guys usually run what? 4-1 ?

1:40. The more oil, the higher risk of burning a piston since lube oil has a lower AKI than gasoline.

[Jeff_G]

When we refer to "white gas" it actually refers to a number of different fuels. Amoco in particular used a lead free "white gas" as a motor fuel. Other "white gas" was used as a stove fuel, latern fuel and even in clothes irons. They were two very different fuels.
One should never use any "modern" motor fuel in a latern, camp stove etc. Very bad results can happen.
You can find information on "white gas" in many of the old advertisements of the day. It was basically replaced by electricity in the 50's! That's why the only places you see it today is places that sell camping supplies.

[RUDERIOT]

a VERY well known engine builder & racer told me face to face that they used 3 qt. oil in 55 gal. gas in thier F-1 circle boat. I do'nt have the nerve to try it!!!

[Just Add Ice]

Jeff is right about the fuel, & if I'm thinking right Mecury listed it as a alternate in the owners manual back in 1969. I had a 125hp. that I used it in all the time. Never had any problems.