Mixed gas for outboards - is chainsaw oil the same, and how do you measure by the ounce?

NickR

NickR

Well-known member
Alright, I'm going through more boat gas this year than the last several put together. I still haven't figured out a good way to measure out the oil for mixing a 50:1 ratio - 3 oz to the gallon, or 5 oz for two gallons according to the oil bottle. I have a gallon bottle of 2cycle marine oil. What if I mixed up a gallon of chainsaw gas and used the little empty 3oz bottle to measure my two cycle marine oil? What if I used the 3oz chainsaw oil in a gallon of gas for the boat motor?

As usual, I'm sure I'm making this more complicated than need be, so what's the simple answer on measuring oil for mixed gas?

Thanks!

NR
 
Marine 2 cycle oil is for water cooled engines, you want to use the TCW2 designation, Other 2 cycle oils are for air cooled engines, like your chainsaw. Is it the same or close? maybe, but I'd use the correct oil.
Most quart engine oil bottles have a measuring "strip" along the side, 50-1 uses 16 oz. per 6 gal, a little extra wouldn't hurt anything so you don't have to measure like a chemist.
What I don't understand is why your mixing such a small amount. Boat tanks are either 3 or 6 gal. or you can mix up a 5 gal container and refuel from that.
 
What I do is buy a 16 oz bottle a gallon jug of 2 stroke oil. I use the markings on the 16 oz bottle to measure out the oil I put in & keep refilling the 16 oz bottle as I need too. I rarely ever burn more than 3 gallons in a trip, so this works well.
Each gallon of gas in the boat tank gets ~2.5 oz of oil out of the 16oz bottle. When I fill my 2 gallon can, it gets ~5 oz.
It does not have to be exact, if you mix 45:1 one tank and 55:1 the next, its not going to kill your engine.
Dont over think it.
 
I don't know what you have in your area, but most marine supply stores sell measuring bottles for mixing oil.
Makes it a lot easier, the bottle is marked on the side with the different mix ratios.
Just fill oil to the mark for how many gallons of gas you just filled.
 
Alright, I'm going through more boat gas this year than the last several put together. I still haven't figured out a good way to measure out the oil for mixing a 50:1 ratio - 3 oz to the gallon, or 5 oz for two gallons according to the oil bottle. I have a gallon bottle of 2cycle marine oil. What if I mixed up a gallon of chainsaw gas and used the little empty 3oz bottle to measure my two cycle marine oil? What if I used the 3oz chainsaw oil in a gallon of gas for the boat motor?

As usual, I'm sure I'm making this more complicated than need be, so what's the simple answer on measuring oil for mixed gas?

Thanks!

NR
Click to expand...


I asked the same question about air cooled vs water cooled oils and interchanging them. the consensus was that it was much better to put air cooled oil in a water cooled enging, vs. the alternative. The thought was that water cooled oil (tcw3) wouldn't hold up to the aircooled temps.

T
 
I agree that over-oiling is not a great thing, but unless you REALLY over do it, it wont hurt the engine.
 
Nick, Todd is right about the air cooled vs water cooled oil. Too much oil will displace fuel in the fuel/air mix and cause the engine to run lean. You can get by with it most of the time until some thing bad happens usually at the worst possible time. Get a plastic baby bottle to measure oil with, you can carry a spare shot of oil in it too.
 
I mix small amounts because my primary motor is a 4hp Suzuki with a self contained gas can that holds about a gallon of gas or less. I top it off every time I use it and normally don't go through a lot of boat gas, so my "boat gas filler can" is 2 gallons.

Thanks for all the info, gentlemen!

NR
 
If you dont use a lot at one time, make sure to put in some Staybil in your 2 gallon, especially if you are using gas w/ethanol in it.
I have learned this lesson the hard way.
 
Nick,
I run larger motors then you so I go through more oil. Plus the rental boats use 50/1 so I can always use mixed gas around here.

What I do is to mix 6 gallons at a time and I think that works out to a 16 oz bottle. Then I refill that bottle from the gallon jug.

I would say get a container that holds the correct amount of oil to mix your container and use that or like the others said go with the measure on the side of the bottle. A little extra doesn't hurt.

Another thing instead of trying to keep gas over the winter ( or if I don't know the mix rate or what it was mixed for) I will burn it through the plow truck or one of the daily drivers. Mixed in with a half tank of gas it doesn't hurt and think and its an easy way to get ride of gas and start fresh. All the rental boat gas goes through the plow truck every winter.
 
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