Oil/Fuel Mixture tester

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wreckless

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Is there some type of tester to check the fuel/oil mixture ratio sort of like a hydrometer used to check batteries?
 
O

Outsider

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Re: Oil/Fuel Mixture tester

Not that I ever heard of. Let us know if you find one ...
 
CATransplant

CATransplant

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Re: Oil/Fuel Mixture tester

wreckless said:
Is there some type of tester to check the fuel/oil mixture ratio sort of like a hydrometer used to check batteries?
Click to expand...

Never heard of one, but it would be useful, I think. I'm not sure how you'd do it, though. Interesting idea.
 
N

nathan104

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Re: Oil/Fuel Mixture tester

It is called an outboard. If it smokes, there is too much oil. If it overheats and screeches to a halt, not enough.... :)
 
jtexas

jtexas

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Re: Oil/Fuel Mixture tester

I believe you could do it with a scale. Put some 50:1 mix on one side, and the same quantity from your tank on the other. Same or heavier, plenty of oil. Lighter, not enough. If you tried to use the specific weight, you'd have to compensate for temperature. come to think of it, you're supposed to compensate for battery acid temp, but I never do.
 
C

Coors

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Re: Oil/Fuel Mixture tester

jtexas; it is mixed by ratio, not weight, but I think you are on a roll.
 
Drowned Rat

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Re: Oil/Fuel Mixture tester

You could make some sort of hyper sensitive viscosity gauge, but even that would have to be calibrated against known mixtures. It would be much easier to just start over with new gas! :)
 
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wreckless

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Re: Oil/Fuel Mixture tester

The reason I posed the question is I disconnected my VRO and started mixing my oil and gas. The problem was I didn't know exactly how much gas was in my 65 gallon tank. The fuel gage read 1/4 tank but I still didn't know exactly how much gas was in the tank. My fishing buddy is an engineer and he asked why I didn't just get a tester and I told him I didn't think one existed which is why I asked the original question. Using the motor as an indicator is great if you have too much oil but I'm not keen on that is the mixture is too low. Just curious.
 
QC

QC

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Re: Oil/Fuel Mixture tester

I'll bet a good oil sampling lab could do it. How important is this to you? Caterpillar dealers have this capability onsite and it is probably less than $20 per sample. Also, they do use a hydrometer for specific diesel fuel gravity, there may be a scale for Gasoline/oil mix too.

You could call them and ask. Ask for the manager of the Oil Lab and if he/she blows chunks try the engine shop. Truck or Machine.
 
Tredeb

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Re: Oil/Fuel Mixture tester

I think I would just take a best guess and add 10%-15% on the fuel remaining in your tank and put in the appropriate amount of oil. As mentioned before, it will just smoke if you get it a little rich. Remember, err on the side of caution, a new set of plugs is cheaper than a new powerhead.

Trev
 
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wreckless

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Re: Oil/Fuel Mixture tester

I guessed at the amount of fuel in the tank and mixed appropriately and then topped the tank with correct oil/fuel mixture and have had it out about 4 times since then and it runs fine. You would think that someone would have designed some sort of tester for this by now. I would think that a lot of other boaters have had similar problems.
 
jtexas

jtexas

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Re: Oil/Fuel Mixture tester

imported_Coors said:
jtexas; it is mixed by ratio, not weight, but I think you are on a roll.
Click to expand...

;)

I'm sure you'll agree that gas mixed with oil will be heavier than 100% gas........therefore, a gallon of 100:1 will weigh less than a gallon of 50:1....and a gallon of 30:1 will be heavier than a gallon of 50:1.......problem is, the precise specific gravity of gasoline depends on (apart from temerature) what's in it. Octane rating, oxgen content, MTBE vs ethanol....

But lets assume a weight of 6.3 lbs per gallon for 87 octane unleaded E10; if you know how much the oil weighs, you can calculate the ratio. Since we know its heavier than water, lets assume 9 pounds.

At those weights, a gallon of 50:1 premix would weigh about 6.35 pounds (.9804 gal of gas at 6.3 plus .0196 gal of oil at 9).

A gallon of 100:1 would weigh about 6.33 pounds. 30:1 would weigh about 6.39.

but to determine if you're over or under, you don't need the specific weights - you just have to compare what's in the tank to the same quantity of 50:1
 
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wreckless

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Re: Oil/Fuel Mixture tester

"if you know how much the oil weighs, you can calculate the ratio. Since we know its heavier than water, lets assume 9 pounds."

Isn't oil lighter than water or does it float on water for some other reason? If you have water in your oil it is always on the bottom of the tank.
 
jtexas

jtexas

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Re: Oil/Fuel Mixture tester

uh......weren't we talkin bout heavy water?...........yeah, that's the ticket...........

:D
 
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