Another Ethanol Question - Adding Fresh Fuel to Older Fuel

[minuteman62-64]

I've looked at the posts here and some on-line references. One thing is not clear to me. What happens if I have a small amount of old (say 90 days) fuel in my tank and fill the tank with new fuel. Will the old fuel mix with the new fuel and form a mixture with slightly different phase separation charactics? Or will the old fuel pool in the bottom of my tank and eventually form a phase separated layer that will cause me problems? In my case, I'm running a 2-cycle motor from a 6 gallon portable tank, so I'd be potentially mixing five to five and a half gallons of new fuel/oil mix with one-half to one gallon of older fuel/oil mix.

Or should I just dump the older fuel in my truck and burn it up before it gets to the problem stage?

 

[tx1961whaler]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

You have a 6 gallon portable tank?
You will have no problems with ethanol mixes at all.
The overblown concerns with phase separation will only be evident with large tanks that have much more opportunity for water ingress from leaky fittings.
And 3 month old fuel isn't old.

 

[rickdb1boat]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

With such a small amount and being 3 months old already, I would just use the remaining fuel from the tank in the truck and start fresh.

 

[GA_Boater]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

My opinion - fill it up and use it.

 

[JimS123]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

Its a non issue. If you keep it more than 3 months, add Stabil to it.

If you really want to have a problem put it in your truck. If it was made in the last 30 years or so and has a computer and catalytic converter it won't like that 2 cycle mix at all!

 

[Silvertip]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

Again -- 90 day fuel is not "old" fuel and will mix just fine with "new" fuel that is likely already 10 days old or more. Stop worrying about this stuff and go boating. Use a fuel system treatment and that fuel will be just fine six months from now. Adding stabilizer at the end of the storage period does not make fuel fresh again.

 

[minuteman62-64]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

Its a non issue. If you keep it more than 3 months, add Stabil to it.

If you really want to have a problem put it in your truck. If it was made in the last 30 years or so and has a computer and catalytic converter it won't like that 2 cycle mix at all!

Looks like the answer is just keep using it, and, when the tank is almost empty, fill it up again.

Given that, it's academic, but, what's the problem with a small amount of 2 cycle-mix in a full or almost full tank of gas in my truck. The good folks at Toyota tell me that oil comsumption of up to about 1 qt./1000 miles is acceptable. If I added 1 gallon of 50:1 2 cycle-mix to 16 gallons of fuel in my truck it seems like I'd be subjecting it to a much lower percentage of oil in the fuel than would occur under Toyota's spec. for "acceptable" oil consumption (whether 1 qt./1000 miles of oil consumption is acceptable with today's motors is, of course, arguable). Particularly given that 2 cycle oils are designed to be consumed in the combustion chamber with little residual (low ash).

Is there some additave in the 2 cycle oils that would contaminate the catalytic converter as a result of combustion?

 

[GA_Boater]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

Don't forget if you are using 1 qt./1000 miles and add oil to the gas the computer might interpret things incorrectly. Why risk damage for 4 bucks worth of gas. But then again it might not harm anything.

 

[JimS123]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

Looks like the answer is just keep using it, and, when the tank is almost empty, fill it up again.

Given that, it's academic, but, what's the problem with a small amount of 2 cycle-mix in a full or almost full tank of gas in my truck. The good folks at Toyota tell me that oil comsumption of up to about 1 qt./1000 miles is acceptable. If I added 1 gallon of 50:1 2 cycle-mix to 16 gallons of fuel in my truck it seems like I'd be subjecting it to a much lower percentage of oil in the fuel than would occur under Toyota's spec. for "acceptable" oil consumption (whether 1 qt./1000 miles of oil consumption is acceptable with today's motors is, of course, arguable). Particularly given that 2 cycle oils are designed to be consumed in the combustion chamber with little residual (low ash).

Is there some additave in the 2 cycle oils that would contaminate the catalytic converter as a result of combustion?

Your 2-stroke OB is old technology that will run OK with most any crap in the tank. Just like my 35 year old classic car.

OTOH your new car is a marvel of computerized technolgy that senses changes in the fuel, air, combustion, etc. Google adding oil to gas in a new car and see what the pundits have to say.

On the other other hand, OMG is that for real from Toyota? I had old cars in the 1950's that were "oil burners", smoked like heck and didn't use a qt in 1000 miles. If I had a car that burned that much oil it'd be in the junkyard before you could spell out r-i-c-e-b-u-r-n-e-r. Sounds to me like the "good" folks at Toyota are just pta so you won't bring back a lemon.

Anywayyyyyy....way off topic. I run 9 month old stabilized gas in the first tank in the Spring and can't tell the difference. I can't add new gas because the tank is always full. My second tank of fresh gas runs just like the first.

Don't worry...be happy.

 

[minuteman62-64]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

On the other other hand, OMG is that for real from Toyota? I had old cars in the 1950's that were "oil burners", smoked like heck and didn't use a qt in 1000 miles. If I had a car that burned that much oil it'd be in the junkyard before you could spell out r-i-c-e-b-u-r-n-e-r. Sounds to me like the "good" folks at Toyota are just pta so you won't bring back a lemon.

Anywayyyyyy....way off topic. I run 9 month old stabilized gas in the first tank in the Spring and can't tell the difference. I can't add new gas because the tank is always full. My second tank of fresh gas runs just like the first.

Don't worry...be happy.

At risk of straying further off topic - from my 2007 Tacoma Owner's Manual: Oil consumption: Max. 1.0 L per 1000 km (1.1 qt./600 miles)

My wife's 2006 RAV4 has the same language and, in fact, at 84,000 miles is consuming at about 0.7 qt./1000 miles. You'd better believe the good folks at Toyota are covering their collective asses.

 

[Scott Danforth]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

one of the epa tests for evaporative emission compliant fuel tanks is to let the fuel sit for a minimum of 14 days to allow it to separate, then to see the effects of the phase separated fuel and ethanol has on the base material at various temperatures. however if you plan on using the boat, fill up and go boating.

on another note, Ford allows up to 1 qt every 800 miles as normal oil consumption. Toyota is not to bad at 1000 miles

 

[JimS123]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

At risk of straying further off topic - from my 2007 Tacoma Owner's Manual: Oil consumption: Max. 1.0 L per 1000 km (1.1 qt./600 miles)

My wife's 2006 RAV4 has the same language and, in fact, at 84,000 miles is consuming at about 0.7 qt./1000 miles. You'd better believe the good folks at Toyota are covering their collective asses.

I don't doubt your experience nor what the owner's manual says.

I owned a 1967 Pontiac 400-4BBL that had ~150,000 miles on it when I sold it. I currently own a 1980 Bonneville with 184,000 miles on it now. I have had countless other GM products - L-6s, V-8s, L-4's and V-6s. I change my own oil and have NEVER had an engine that consumed ANY oil in 3000 miles.

Now I know why I don't like Toyodas.

 

[Texasmark]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

Looks like the answer is just keep using it, and, when the tank is almost empty, fill it up again.

Given that, it's academic, but, what's the problem with a small amount of 2 cycle-mix in a full or almost full tank of gas in my truck. The good folks at Toyota tell me that oil comsumption of up to about 1 qt./1000 miles is acceptable. If I added 1 gallon of 50:1 2 cycle-mix to 16 gallons of fuel in my truck it seems like I'd be subjecting it to a much lower percentage of oil in the fuel than would occur under Toyota's spec. for "acceptable" oil consumption (whether 1 qt./1000 miles of oil consumption is acceptable with today's motors is, of course, arguable). Particularly given that 2 cycle oils are designed to be consumed in the combustion chamber with little residual (low ash).

Is there some additave in the 2 cycle oils that would contaminate the catalytic converter as a result of combustion?

Good point and so true. Until the industry went to Stellite coated valves and all the other goodies that went with unleaded fuel I always used an upper cylinder lube in my road machines.

Course nowadays, even though I live in the country and every trip is in excess of 10 miles, my vehicle mileage is like....well I just traded an '05 Dodge 1500, 4 door, 4.7 with 19,000 miles and an '07 Dodge 1500, 2 door, Hemi with 13,000 miles in on my new Silverado, so I really have no idea any more just how long my engines will last, but for the fully decked out crew cab with 20" chrome skin wheels, deluxe running boards, and all the goodies I only had to hock up $5k to seal the deal....must be a message there....but the only engine I ever lost was a '75 70 hp Evinrude and that was due to a closed shut thermostat with no bypass valve and no alarm that I had recently bought from a friend.....friend......yeah right and I happened to be at about 45 mph when it happened and I couldn't believe how fast that boat settled in the water. What ever happened to the overrun clutch in the F gear of the lower unit? It apparently didn't work either because I just about knocked out my dentures on the dash coming to an abrupt stop.

Ho hum. This is worth what you paid for it, grin.

Mark

 

[HT32BSX115]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

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[minuteman62-64]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

I don't doubt your experience nor what the owner's manual says.

I owned a 1967 Pontiac 400-4BBL that had ~150,000 miles on it when I sold it. I currently own a 1980 Bonneville with 184,000 miles on it now. I have had countless other GM products - L-6s, V-8s, L-4's and V-6s. I change my own oil and have NEVER had an engine that consumed ANY oil in 3000 miles.

Now I know why I don't like Toyodas.

I'm guessing the oil spec. for those vehicles was in the 10-30 to 20-50 range. My Tacoma and RAV4, for the US models, spec 5-20 to help meet Federal milage standards (the spec for Canadian models is 5-30). I think the lower viscosity oil impacts the consumption. I've recently switched to 5-30 with the idea that I'll accept a slight fuel comsumption penalty for possibly better engine protection.

 

[HT32BSX115]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

...

 

[minuteman62-64]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

Hmm. I thought this was a gasoline thread on the merits of blending "fresh" gas with "old" gas in a boat........

I think it is called "thread drift" or something like that. Whatever it is, I've helped it along. But, I got a lot of good input on my original question, and now know how to deal with the last gallon or so of fuel in my tank

 

[RogersJetboat454]

Re: Another Ethanol Question - Adding Fresh Fuel to Older Fuel

My 2 ?...

- 1 gallon of 3 month old fuel is a non-issue, especially if the tank vent has been used correctly. Top off with gas/oil mix and happy boating.

- 1 gallon of fuel-oil mix added to at tank of fuel on a modern vehicle especially right before filling the tank will be a non-issue. Compared to some of the mythical crap guys feel the need to add to their fuel on a regular basis on said modern vehicles, a 50:1 fuel mix in a gallon of gas (which only contains 2.56 Oz of oil) is going to be broken down to a much higher ratio in the fuel tank of a truck. In a 25 gallon tank it would be 1250:1, not a problem.

- Owners manuals giving acceptable LIMITS are not reality. Most new cars out there wouldn't burn a whole quart in 10K miles. If people want to continue that discussion, I suggest posting a new thread.