Outboard Oil ratio Question

[zippy83]

Hi All,

I have an 2 stroke 50HP outboard that uses 50:1 ratio. I am planning in the coming weeks a bigger fishing trip and have a question about how much 2 Stroke oil I should put in 5 Gallons. I have a 12 gallon tank but the 5 Gallons are just for in case I start running low.

The chart says the following as you may already know

1GAL = 3oz
3GAL = 8oz
6GAL = 16oz
12GAL = 32oz

So I am confused on how much OIL I need to put on 5 GAL. If one GaL takes 3 OZ then 5 GAL should take 15oz but then again 6GAL takes 16oz...

How should I calculate this correctly

Thanks
Zipp

 

[Don Hansen]

Re: Outboard Oil ratio Question

Actually, they are rounding off the numbers. 50 to 1 for 1 gallon would be 2.56 oz. If you multiply 2.56 by 5 you get 12.8 0z. Just out of curiosity, 2.56 times 6 equals 15.36. Looks like they want to play it safe. Rather have the ratio rich than lean.

Personally, I always add an ounce or 2 extra when mixing up 6 gallons for my 1980 and 1974 motors.


DLH

 

[GA_Boater]

Re: Outboard Oil ratio Question

Go to K-Mart and buy a 3 buck oil measuring bottle. There are other places that sell them. Simple to use. If you put 5 gallons of gas in the tank, pour the oil in the bottle to the 50:1 5 gal. mark and dump it in the tank.

 

[pootnic]

Re: Outboard Oil ratio Question

Switch to metric......

 

[zippy83]

Re: Outboard Oil ratio Question

Actually, they are rounding off the numbers. 50 to 1 for 1 gallon would be 2.56 oz. If you multiply 2.56 by 5 you get 12.8 0z. Just out of curiosity, 2.56 times 6 equals 15.36. Looks like they want to play it safe. Rather have the ratio rich than lean.

Personally, I always add an ounce or 2 extra when mixing up 6 gallons for my 1980 and 1974 motors.


DLH

I am also running a 1974 Merc Outboard. So on 5 Gallons I can safely add 13 - 14oz of oil?

 

[zippy83]

Re: Outboard Oil ratio Question

So it is ok to put a little more oil then expected?

 

[GA_Boater]

Re: Outboard Oil ratio Question

If you want to, but why? The motor is designed to run at 50:1. In my opinion adding extra is a waste of oil. An extra ounce or two of oil won't stop a motor from blowing up if it's already on it's last legs.

 

[zippy83]

Re: Outboard Oil ratio Question

If you want to, but why? The motor is designed to run at 50:1. In my opinion adding extra is a waste of oil. An extra ounce or two of oil won't stop a motor from blowing up if it's already on it's last legs.

I wasn't sure about it that is why I asked. So I guess 13oz on 5gal should do the job just right....

 

[JB]

Re: Outboard Oil ratio Question

Your outboard will run fine on anything from 24:1 to 50:1. It is just with more than required you get more smoke, stink and carbon deposits.

Oiling outboard fuel is like watering a horse; More than required is okay. Less than required is possibly fatal.

 

[zippy83]

Re: Outboard Oil ratio Question

Your outboard will run fine on anything from 24:1 to 50:1. It is just with more than required you get more smoke, stink and carbon deposits.

Oiling outboard fuel is like watering a horse; More than required is okay. Less than required is possibly fatal.

Thank you

 

[ondarvr]

Re: Outboard Oil ratio Question

Switch to metric......

Metric is very easy, it's just hard to find a metric gas pump, unless you go to Canada, there are a few metric gas cans out there though.

The easiest way is to use %, 50:1 is 2%

128 oz (1 gallon) X 2% = 2.56 oz

I just use the bottle GA recommended, I try to save what little brain power I have to out smart fish.

 

[GA_Boater]

Re: Outboard Oil ratio Question

Metric is very easy, it's just hard to find a metric gas pump, unless you go to Canada, there are a few metric gas cans out there though.

The easiest way is to use %, 50:1 is 2%

128 oz (1 gallon) X 2% = 2.56 oz

I just use the bottle GA recommended, I try to save what little brain power I have to out smart fish.

Maybe I better get another bottle cause it's not workin' for me. LOL.

I just add whole gallons of gas or is that whole 3.78541178 litres and go to the mark and dump. I like simple things for simple solutions.

 

[pootnic]

Re: Outboard Oil ratio Question

I actually thought I`d get more comments.
Then the one I do get is very civil,plus it gives an excellent solution...2% rule,nice.

Disappointing...)

 

[Grub54891]

Re: Outboard Oil ratio Question

I've always called it 3oz per gallon,never toasted one yet,not smokin either....
Grub

 

[GA_Boater]

Re: Outboard Oil ratio Question

I actually thought I`d get more comments.
Then the one I do get is very civil,plus it gives an excellent solution...2% rule,nice.

Disappointing...)

Why? No matter how the gas is delivered, you still have to measure the oil. If I was getting gas in liters, I would get a metric bottle. Metric or U.S. liquid doesn't make much difference.

 

[pootnic]

Re: Outboard Oil ratio Question

Statement may be true...but
Up here most(all ?) of our oil bottles are measured off in ml's.Also,on the back of most bottles,they give common ratios(25:1;40:1 50:1 etc),for regular used increments.
To figure it out is pretty simple though;I just take the amount of liters, times it by 20 (or 2 and add a 0)...and that's how much oil to add in ml's.(really just 2%)
Most times I add the oil in at home,say 200ml's and then add 10L's gas.(then top of the truck with whatever)

In your case 5 gal's x 3.78 = 18.9 L's x 20 = 378ml....somewhere in the 350/400ml range depending how often I've been running my outboard,is what I'd add.
If I use the x's 2 method;I'd use 19L's doubled is 38,add a 0 to the 38...so 380ml.

Anyways,I was just messing a bit...you have some good advise for gallons...

 

[GA_Boater]

Re: Outboard Oil ratio Question

All of our quart bottles of TC-W3 have ounce marks with a semi-clear stripe. I worry about the accuracy using them. But it's probably "close enough".

 

[Don Hansen]

Re: Outboard Oil ratio Question

All of our quart bottles of TC-W3 have ounce marks with a semi-clear stripe. I worry about the accuracy using them. But it's probably "close enough".

That's why I add an ounce or two from another bottle. I don't measure that extra bit, I just add it.

DLH

 

[Scubaslife]

Re: Outboard Oil ratio Question

3 oz. per gallon is a good general rule. It won't kill your motor is you're a little high but it could run hot and potentially cause damage if you're low. So it's a safe bet to round up.