Re: oil injection
not in a area where i can buy premix worry about getting the right mixture have built in gas tank sometimes hard to get right quanity
bgbass.1's technique works well. I'e done it that way.
Here's another way that I've used for many years.
Although it's important to mix your gas and oil fairly accurately, don't get to compulsive about it, you can do a certain amount of rounding to make it easier. With my built in tanks, I've never used a measurement more precise than quarts and 1/2 quarts for oil. I just buy my oil in quarts, and eyeball the 1/2 quart (i.e. pint) mark. I don't use a measuring device. For what it's worth, you can usually buy cases of quarts for a similar per gallon price as gallon packaging or bulk.
First of all, if you're tanks have a direct fill, depending on the shape of the tank you might be able to make an accurate dipstick and estimate in advance how much fuel will be going in.
Generally I don't fill completely full but just stop at some increment of 6 gallons and add 1/2 quarts of oil accordingly. I add the oil right into the stream of gasoline so it will mix it up. I do this through a large funnel, pouring the oil into the gas as it swirls through the funnel... first 1/2 quart with the first 6 gallons, etc. You don't have to do this consistently through the 6 gallons, just pour the oil into the funnel as you begin the gas. Of course if I know 12 gallons is going in there, I just do the whole quart.
If I fill completely, I still make it simple and just round to the nearest 6 gallons and add oil in increments of 1/2 quarts. I don't bother measuring to the exact ounce of oil.
Obviously, sometimes that last 1/2 quart goes in, but I end up adding less than 6 additional gallons of gas. Or, as I get near the end, if I think I'm not going to get much more fuel in, I won't add any oil for the last gallon or two. Anything more than that and I'd go ahead and put in another 1/2 quart.
In a full tank of gas, whether the last couple of gallons is mixed a little rich or a lean, will be insignificant. You can do the math, but my guess is that the fuel in the tank will never be "richer" than 45:1 or "leaner" than 55:1, neither of which will do any harm for occasional use.
Of course if the tank is empty, I know exactly how much oil I'll need to fill it completely, but still round to the nearest 1/2 quart.
Hope this makes sense.
Good luck.
