I have a old Johnson 9.9 and the other day I was looking up how to mix a 51 ratio and I also went to the store to buy a mixing glass. Now my qustion is on the mixing glass it has 1.5 per gallon of gas.,I also looked it up and it tells you 2.5 per gal. So what's right?.

50:1 ratio is usually 2.6 ounces of oil to 1 gallon of gas - although some oil manufacturers list 50:1 as 3 ounces of oil to 1 gallon of gas.

Guss , you were smart to get the mixing glass.

I was in a small engine shop one day and the guy there was trying to sell me one. He called it an ' Idiot cup '

The logic behind that was if you didn't use one you are an idiot. Mixing the oil and gas in the correct measure as close as possible is very important. Your machine will run so much better than eyeballing it.

I have had an idiot cup ever since.

Forget all the complicated measuring.
Mix one pint to five gallons. Good for everything.

Was at a large marina once and a beautiful boat there was being delivered from England. A crew member was going to mix some fuel for their dingy and he was struggling to convert quarts and pints to liters. He had a six gallon tank and the appropriate size can of 2-stroke oil. Finally I told him to pour the oil in his tank and fill it with gas. This was about 1970 when we mixed at 16 to 1.

you need to check the back of the oil bottle what oil are you using

most stores that sell boat supplies sell ATWOOD mixing bottles very handy easy to use although technically a mason jar with a line would work also

you can put a touch of gas in the bottle to rinse the last of the oil out then pour it all in the tank

I use the mercury quicksilver oil I buy by the gallon it is 8 ounces for 100:1 and 16 ounces for 50:1 on 6 gallons

I have a 6 gallon tank and I keep a spare 6 gallon can opposite the tank next to the battery

my 1991 Mariner / Yamaha 25hp is supposed to be 100:1 but I recall there being some issues with guys actually running 100:1 back then so I run 75:1 and it is going strong and not fowling any plugs either.
the bottle doesn't have a 75:1 but it is the middle between 100:1 and 50:1 for me 12oz per 6 gallons of gas is 75:1


we have only gone through the 6 gallon main a few times but once on the Mississippi middle of the channel 2 miles down stream from the launch and once running to weigh in on an all night tournament.

for the mercury oil which seems to be very standard

I use the Stihl bottles of synthetic oil for chain saws. One little bottle does a gallon of gas. I'm a big believer of synthetic oil. No muss no fuss.

I saved an empty fuel stabilizer bottle and filled it with the mix oil, makes measuring very easy and clean!

A ratio rite is your friend , I've had one for about 35 years now

50 to 1 is 50 liters of gas to one litre of oil.
Or 5 liters of gas to 100ml of oil.
Or 1 liter of gas to 20ml of oil
Its like grade two math,lol..

40 to 1 is 40 liters of gas to 1 liter of oil
or 4 liters of gas to 100 ml of oil
Or 1 liter of gas to 25 ml of oil.

and so on.

Boco, your ability to do mathematical computations is impressive.

I weigh the oil on scale. I only use about 2 gals at the most each year.

Most in the states do not use the metric system…even though it makes most every calculation easy to do in your head…..

Thanks alot Pete the bottle I have is way off.

A 6 gallon tank at 1.5 oil =9

6 gallon tank at 2.5 =15 if my math is right.

Standard math always seemed easy to me. Fluid ounces per gallon. It worked for a couple hundred years. Now metrics became necessary for some reason. Same with changing from English language to Spanish. Cave in to everything that comes along.

I use a used quart motor oil plastic bottle. It has the ounces marked on the side. Always one around.or refill your one shot bottles for mixing gallons.

I run Yamalube, Quicksilver or Amsoil. Use high quality and being off a little doesn't matter.
New outboards with blenders vary the mix ratio from 50 to 1 to a 100 to 1 depending on speed.

Don't over think it.

X2
Old motocross guys think a like!

anyone besides me see the mistake on this chart ????

25:1 should be 6 oz
or 50;1 2.5 oz
Then if you multiply across well just forget that lol

Stick to cake baking,lol.

Boco, not everyone has your genius for math.