running gasoline/diesel mix in an emergency

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we are now at the 80% 20% tested. we are getting somewhere.

I dont know what the issue is with this question. It is a question that does have an answer in principle. In practice it is difficult to answer but it certainly can be discussed. The answer "NO..it will blow you up!" is not any kind of rational answer.

Clearly there is a continuum of ratios from perfectly fine to quickly catastrophic and many steps in between. Especially if you throw in additives.

I personally welcome the discussion. Even though I can think of a dozen other factors I would reach for well before considering this move it seems like decent info to store in the back of your head.

Its also clear that many are chiming in without any knowledge or research of the topic.
 
I dont know what the issue is with this question. It is a question that does have an answer in principle. In practice it is difficult to answer but it certainly can be discussed. The answer "NO..it will blow you up!" is not any kind of rational answer.

Clearly there is a continuum of ratios from perfectly fine to quickly catastrophic and many steps in between. Especially if you throw in additives.

I personally welcome the discussion. Even though I can think of a dozen other factors I would reach for well before considering this move it seems like decent info to store in the back of your head.

Its also clear that many are chiming in without any knowledge or research of the topic.

Not all that uncommon.... then many times it's "book/mag/internet knowledge" not practical or real world. That how so many boating urban legends are born and stick. :D
 
For once Soo Valley is right. The question can be resolved by practical experimentation, not involving my boat. Perhaps the OP is lying in wait with a preformed determination and/or this all relates to another thread.
Meanwhile, TF gets lots of clicks, it`s "win-win", or something, for someone.
 
For the experiment, how about testing chainsaw or outboard 50:1 oil....to help it out why not start at 25:1, see what happens...then go down to 10:1 and record results. Heck, why not bring DEF to the party too?
 
"took on ten gallons of kerosine and added two gallons of gasoline."

The more usual emergency mix is a quart of engine oil with each 5 gal of diesel.
 
"took on ten gallons of kerosine and added two gallons of gasoline."

The more usual emergency mix is a quart of engine oil with each 5 gal of diesel.

Yep, looking back it's lucky we didn't blow ourselves up. But that little 4 cyl diesel ran for 16 more years and 300,000 more miles.
 
Dump the vegetable oil in first

I've run three older Ford trucks (7.3L) on waste vegetable oil for a combined 400-500 thousand miles.

All that's necessary is to make sure the oil is filtered clean, preferably before you put it in the tank. I had two tank systems, so that I would start the engines on diesel, then throw a switch to convert over to the veg oil tank. Any older diesel will run just fine on veg oil once the engine is up to operating temps.

In an emergency I would not hesitate to dump clean veg oil into the tank on a boat, but I'm not sure how far a quart of veg oil is going to get you.
 
I recall adding a cup of gasoline to my diesel engine on a very cold day to get my engine started.
 
I recall adding a cup of gasoline to my diesel engine on a very cold day to get my engine started.

I am surprised that this would have helped, since it would INCREASE the autoignition temperature.

The fluid that is used for facilitating cold starting is ether, which has a lower autoignition temperature than diesel.

Ether 160C (320F)
Diesel 210C (410F)

Nick
 
I am surprised that this would have helped, since it would INCREASE the autoignition temperature.



The fluid that is used for facilitating cold starting is ether, which has a lower autoignition temperature than diesel.



Ether 160C (320F)

Diesel 210C (410F)



Nick

The lower autoignition temp of gasoline is correct. However adding some gas can be a starting aid. I used to run an early 60s Cat D379. It can be a tough engine to start in cold weather. According to the OEM operator's manual one of the approved cold weather starting methods was a mixture of 10% gas 90% diesel. We didn't want to mess with that so used a block heater.

Sent from my SM-A125U using Trawler Forum mobile app
 
My old Mercedes called for a gallon of gasoline in each tankful (15 gal) of diesel to help with winter starting. Never a problem and drove it for over 700K miles for business.
As a mileage improver, I don't think it will work without a timing change and even then I don't think it would really shorten the flame delay noticeably.
 
Thank you for this. Live and learn.
Can anyone explain the physics behind this? (gasoline added to diesel helping cold starting)
Could it be different for an engine with glowplugs (like the Mercedes)? Perhaps the added gasoline created some vapour which the glowplug was able to ignite.
 
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Thank you for this. Live and learn.
Can anyone explain the physics behind this? (gasoline added to diesel helping cold starting)
Could it be different for an engine with glowplugs (like the Mercedes)? Perhaps the added gasoline created some vapour which the glowplug was able to ignite.

From my previous post with details from wiki...the added gasoline actually lowers the temp at which diesel fuel will gel. Adding gas helps the fuel to flow. This may not be the only reason, but one that is detailed from several resources.

What Causes Fuel Gelling? This term is pretty self-explanatory, since fuel gelling occurs when the fuel in your tank thickens up enough to look and feel like gel. This only happens when the temperature outside drops below 32 degrees Fahrenheit, though it's most likely to occur at about 15 degrees or lower.
 
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That was my first reaction to the question. Likewise, if you run out of drinking water you can mix it with gasoline. What percentage? Your choice.

c'mon, be sensible. Everyone knows you add urine. Recycle/reuse, much like California from toilet to tap.
 
That was my first reaction to the question. Likewise, if you run out of drinking water you can mix it with gasoline. What percentage? Your choice.

apparently, you are a very bored individual with nothing to do.

I mix my drinking water with salt water. i know what i am doing.

I like to thank all the contributors with valuable information.
 
There was an excellent post above pointing out behavior of common rail is quite different than non turbo’d NA diesels. Current engine is a Cummins with turbo, aftercooler and common rail. What it will tolerate is quite different than an old school Gardner.

Have put cetane boosters, antigel and other supplements into my trucks and diesel cars. The boat sees diesel and biobor. I follow the manual.
 
Not really an answer, but just some info. Gas and oil pipelines that transport fuels to tank farms around the US, push any intermix (gas/diesel combo) into the gas tanks and keep the diesel tanks pure as possible. Gas engines can tolerate impure fuels better than diesel in general, and they go to great effort (and fuel oil losses), to keep the product clean and pure.
 
What are you using?


Archoil AR6500. Before that AR6200. Available online at archoil.com, Amazon and ebay. Sometimes found at truck stops and diesel repair shops.
Detailed info at archoil.com


Older Cats like the D379 usually ran on #3 diesel. Especially in the 1960s. It was a selling point for Caterpillar. Although the #3 of those days was better than the #2 of today.
 
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What are the options if any on adding gas to diesel to make a few more miles.

any percentage mix that are acceptable and or addling ATF or something like that to the mix.

ZERO GAS!!!!!
ATF can add a bit of lubricity to diesel FOR OLDER diesel enjines only, but will create injector nozzle deposits, ruining efficiency in long term.
I would never do it.
Approved additive for diesel only.
 
c'mon, be sensible. Everyone knows you add urine. Recycle/reuse, much like California from toilet to tap.

What are Arizona and Colorado? Chopped liver?
Besides, drinking urine will apparently postpone death from dehydration. ;)
 
Archoil AR6500. Before that AR6200. Available online at archoil.com, Amazon and ebay. Sometimes found at truck stops and diesel repair shops.
Detailed info at archoil.com

There are so many diesel additives out there and they pretty much all claim the same things. Hard to know what works vs. snake oil. I can't say I see a noticeable performance difference though I don't accurately track mpg regularly. I was using FPPF and also FuelOx. (I believe FPPF is endorsed by Yanmar. It's definitely recommended by Mack Boring)

Now I only buy ValvTect diesel as it alledgedly already has a good additive package and I use their BioGuard product for winter storage as they recommend. Other than that I don't normally use other additives, or if I do, I use them at a more diluted mixture when adding to ValvTect diesel.

https://www.valvtect.com/
 
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Not to be a Contrarian, but...

In the 1980s in Colorado I recall a couple diesel car owners who added a small percentage of gasoline to their vehicles to improve cold weather (20°F and below) starting. As overnight temps would approach -30°F in the mountains during the winter, this supposedly prevented gelling of the diesel fuel.

No personal experience with this, and certainly cannot recommend it. Plus, I don't think most bosters encounter these kinds of temperatures.
 
Gasoline definitely does not like 16-17 to 1 compression ratio,, and becomes VERY volatile including total destruction of a diesel engine..>>>Dan
My Mazda with a 2.0 skyactive gasoline engine has a 14.0:1 compression ratio.
 
My Mazda with a 2.0 skyactive gasoline engine has a 14.0:1 compression ratio.
I'm guessing that computer controlled sequential fuel injection helps a lot with that.
Racing spark ignition engines can run 14+:1 CR with alcohol fuel blended with nitro, too.
 
Just say NO

Lurker here - with a dream of retirement whiles still keeping my feet wet.

While I do not have the wealth of experience with smaller Marine Engines, I have 40 years of sailing with large-slow speed (<150rpm) diesel engines as well as medium speed diesels (~750rpm).Now, having said that, petroleum expands at the same rate no matter how big the engine. Therefore, the piston linear speed is the same as a small engine.
Others have covered volatility of storage issues.
Mixing fuel is done, but with way more instrumentation than you would have. 'Normal' road diesel is 2.5 Cst (Centistokes) on the kinematic viscosity scale. At sea, our vessels ran residual fuel, heated to 280-f to obtain an ideal injection temp of 10~12 Cst on the low-speed main engine. The fuel is heated/regulated using a very sophisticated controller called a viscosimeter. It regulates the heating based on measured Viscosity in the fuel pipe being delivered to the engine.
So, again, diesel is 2.5 Cst, Gasoline is 0.88 or so. Kerosene is not so regulated and can be anywhere from 2.0~5Cst.

The fuel we were given to burn is anywhere from 380~500 Cst. 500CsT being about the consistency of road tar. Many times, a vendor will take road tar or some other 'residual fuel' and using "cutter stock" (diesel) mix it until in meets the spec that was ordered. So, I can personally attest that when you mix various grades and thicknesses of fuel and IT WILL separate in the storage tank, just like cream from raw milk. How long? Depends.
LUBRICITY - The main engines (130rpm) liked 13Cst. the Generators (750rpm) liked 8CsT. We had two Viscosimeters, one for main engine and one for the three generators. IF the operator did not get the viscosity correct, or controller failed, the fuel might get too thin, loose its lubricity from being too hot, and then the fuel pump plunger seizes within the barrel of the fuel injector. When this happens, the solid lifters below the injector have to LIFT something, and it is usually the whole injector that gets lifted off its mounts.
CETANE/OCTANE - Others have covered this well. Gasoline, even the higest octane is very explosive. So if it can get past the fuel pump, it could very well pressure-ignite in your injectors.
You would be far better off using lube oil cut with diesel than diesel cut with gas.
And yes, on the ships I worked on we 'recycled' the used lube oil into the fuel. But when you are burning 135tons of fuel a day, it might be a small percentage.
And just to make operations more interesting, changing from this heavy residual fuel (380~500/120c~150c) to regular Marine Diesel (2.5~4/ Ambient Temp) is problematic and has to be done each and every time a large ship enters (and wxits) a SECA (Sulfur Emissions Control Area) of which Europe and North America are now.

So... now you have some of the technical background.

To sum it up - Please do not do this.
 
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hfforeman, one hell of a 1st post. welcome to the forum

I was just about to say the same thing Soo. For a lurker, that's a hell of a first post. Nicely done. Hope you will continue to contribute.
 
Historically, there were farm tractors you would start on gasoline and then run it on diesel. Separate tanks.
But then during WWII, in Europe, there were trucks running on charcoal
 
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