Run the outboard dry
- Thread starter dlewis812
- Start date
I wonder if it would work just as well having been passed through the kidneys?...
Gasoline benefits from a full tank dosed with "StoreX" The vent line for diesel tank should have a "filter" filled with moisture absorbing granules.
I have several comments here. I’ll start with comments about how I handle fuel for my motors, then I’ll list some information about fuel that some may find interesting.
I have a 1987 outboard on a small fishing boat. It has had it’s carb run dry at the end of each day’s use for as long as I have owned it. That motor still runs great. When I had the heads off to clean sand out of the water passages, I found no scoring in the cylinder walls. I did find about ¼ teaspoon of oil residue in each of the cylinders.
I only put ethanol free fuel in the (vented) tank on that boat. Occasionally, I have brought a range-extender tank on board that was filled with regular pump gas containing ethanol. I always used that gas up first & then switched to the tank with the ethanol free before running back into the docks & shutting down the motor. I have a Racor filter with a clear view bowl on it. I change my filter about every other year. I have had no fuel related problems.
I have a pressure washer that I didn’t drain the fuel out of before letting it sit for about 5 months. After that, it would only run on choke. 2 months later, it would not run at all. A half hour cleaning the carb brought it back to normal. Since then, I drain the carb if I plan to let it sit for a week or more.
When I store gas in cans, I try to rotate it & use it up within 3 months. I have air tight O-ring seals on my cans, to prevent partial fuel evaporation. I don’t use any additives.
Back when I worked in a motorcycle shop part time during college, one of my frequent tasks was cleaning out carburetors that had sat with fuel in them over the winter or longer. I did a lot of that. After speaking with many customers who brought their bikes in to get them running again, I came to the conclusion that leaving regular pump gas to sit for 6+ months is generally a bad idea. In my experience, additives can buy you some extra time, but eventually all gasoline does go bad. With good additives, it may take years, but eventually, it does happen.
Gas goes bad in a few ways. It can break down into other compounds that you don’t want to have in your engine, it can bond with water & it can evaporate. Modern “Gasoline” is actually a mixture of several different chemicals. As such, different components evaporate at different rates. Gas that has been sitting around for a while in a vented container, like the fuel tank on most boats, will loose some chemicals before others, & will get knocked out of spec. This can make your engine run rough. If ethanol is in the gas & you are in a humid environment, then moisture will bond with the ethanol & form a non-combustible sludge that will sit on the bottom of the tank until it gets sucked up into the filter, carb, or injection pump. This can stop your motor from running. The break down into really terrible by-products takes longer & generally produces a noticeable odor.
Modern “Gasoline” is a mixture of several different chemicals. A chemical engineer, who worked at one of the refineries, once explained to me how they choose the formulation for each individual batch. I’m not going to repeat that here, but they now label the gas pumps “Motor Fuel” rather than “Gasoline” for a good reason. Its been that way for a long time. The content of the motor fuels that we buy vary with the season & the prices of various precursors.
Aviation gas comes in a few different flavors. There is blue, green, red & jet fuel. The blue stuff (100 octane low lead) is the most common these days. Av gas has a wonderful mixture of solvents in it. It is great stuff for cleaning out a gummed up carb, but it has a few idiosyncrasies that you want to know about. For one thing, is has a detrimental effect on “normal” motor oils. If you are running av gas, you also should run aero-shell motor oil. Another thing to know about av gas, is that it evaporates faster than most other motor fuels & is more sensitive to being kept in a sealed container. The red stuff is low octane “MO-gas”, for old crop dusters. You don’t want that. The green stuff was extra high octane I think. There may also have been a purple version in the distant past, but I haven’t seen purple fuel in at least 40 years.
Diesel keeps a lot longer than gas, as long as it doesn't get contaminated.
I have a 1987 outboard on a small fishing boat. It has had it’s carb run dry at the end of each day’s use for as long as I have owned it. That motor still runs great. When I had the heads off to clean sand out of the water passages, I found no scoring in the cylinder walls. I did find about ¼ teaspoon of oil residue in each of the cylinders.
I only put ethanol free fuel in the (vented) tank on that boat. Occasionally, I have brought a range-extender tank on board that was filled with regular pump gas containing ethanol. I always used that gas up first & then switched to the tank with the ethanol free before running back into the docks & shutting down the motor. I have a Racor filter with a clear view bowl on it. I change my filter about every other year. I have had no fuel related problems.
I have a pressure washer that I didn’t drain the fuel out of before letting it sit for about 5 months. After that, it would only run on choke. 2 months later, it would not run at all. A half hour cleaning the carb brought it back to normal. Since then, I drain the carb if I plan to let it sit for a week or more.
When I store gas in cans, I try to rotate it & use it up within 3 months. I have air tight O-ring seals on my cans, to prevent partial fuel evaporation. I don’t use any additives.
Back when I worked in a motorcycle shop part time during college, one of my frequent tasks was cleaning out carburetors that had sat with fuel in them over the winter or longer. I did a lot of that. After speaking with many customers who brought their bikes in to get them running again, I came to the conclusion that leaving regular pump gas to sit for 6+ months is generally a bad idea. In my experience, additives can buy you some extra time, but eventually all gasoline does go bad. With good additives, it may take years, but eventually, it does happen.
Gas goes bad in a few ways. It can break down into other compounds that you don’t want to have in your engine, it can bond with water & it can evaporate. Modern “Gasoline” is actually a mixture of several different chemicals. As such, different components evaporate at different rates. Gas that has been sitting around for a while in a vented container, like the fuel tank on most boats, will loose some chemicals before others, & will get knocked out of spec. This can make your engine run rough. If ethanol is in the gas & you are in a humid environment, then moisture will bond with the ethanol & form a non-combustible sludge that will sit on the bottom of the tank until it gets sucked up into the filter, carb, or injection pump. This can stop your motor from running. The break down into really terrible by-products takes longer & generally produces a noticeable odor.
Modern “Gasoline” is a mixture of several different chemicals. A chemical engineer, who worked at one of the refineries, once explained to me how they choose the formulation for each individual batch. I’m not going to repeat that here, but they now label the gas pumps “Motor Fuel” rather than “Gasoline” for a good reason. Its been that way for a long time. The content of the motor fuels that we buy vary with the season & the prices of various precursors.
Aviation gas comes in a few different flavors. There is blue, green, red & jet fuel. The blue stuff (100 octane low lead) is the most common these days. Av gas has a wonderful mixture of solvents in it. It is great stuff for cleaning out a gummed up carb, but it has a few idiosyncrasies that you want to know about. For one thing, is has a detrimental effect on “normal” motor oils. If you are running av gas, you also should run aero-shell motor oil. Another thing to know about av gas, is that it evaporates faster than most other motor fuels & is more sensitive to being kept in a sealed container. The red stuff is low octane “MO-gas”, for old crop dusters. You don’t want that. The green stuff was extra high octane I think. There may also have been a purple version in the distant past, but I haven’t seen purple fuel in at least 40 years.
Diesel keeps a lot longer than gas, as long as it doesn't get contaminated.
The lesson learned is to let your gas engine running out of fuel. Recently I loaned my chainsaw out with that fellow I was adamant about ethanol free gas only. Needless to say he used ethanol gas which was old and it was old Would not work the next day. A trip to the shop and a bill paid. Never will loan out my chain saw again
We don’t have an option in my area. All gas has ethenol. In the fall I run dry all items that won’t be needed over the winter, weed trimmer, edger, power washer, etc. I used to do the same to my outboard, when I had one.
I have never, and will never, bother with running my outboards (or any other engine) dry. Not unless it's going to sit for something crazy like a year or more.
BUT, I never let ethanol touch them, or any small engine I own - leaf blower, chain saw, generator, pressure washer, lawn mower, weedeater ... NOTHING ever tastes a drop of ethanol. EVER.
And I never have any carburetor-related trouble with ANYTHING. And I never use SeaFoam.
Admittedly, I do put Sta-Bil in my fuel cans when I fill them, but that's because I keep a LOT of them and the fuel will often be stored well over a year. If that were not the case, I would use no additives at all. Don't use ethanol, and you won't need them. And you won't need to run your engines dry.
Ethanol is from Hell.
BUT, I never let ethanol touch them, or any small engine I own - leaf blower, chain saw, generator, pressure washer, lawn mower, weedeater ... NOTHING ever tastes a drop of ethanol. EVER.
And I never have any carburetor-related trouble with ANYTHING. And I never use SeaFoam.
Admittedly, I do put Sta-Bil in my fuel cans when I fill them, but that's because I keep a LOT of them and the fuel will often be stored well over a year. If that were not the case, I would use no additives at all. Don't use ethanol, and you won't need them. And you won't need to run your engines dry.
Ethanol is from Hell.
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My great-aunt, a member of the temperance movement, told me the same thing many times. Her brother, my grandfather, was of the opinion that aged Canadian ethanol was in perfect alignment with God’s plan.
I am unaware of premium pump gas being ethanol free in the US. In much of Canada, it is. Perhaps in your area it is. You can find out by taking a small sample & putting it in a glass container with some water. If you shake it up a bunch & the water layer gets bigger, then you have ethanol in the gas. I find it best to use a tall thin glass jar. I put the water in first & mark the level with a sharpie. I then put in about 5 times as much gas before shaking it up. You are typically looking for a volume change that is about 3-8% of the amount of gas you add, but any increase in the size of the water phase indicates the presence of some ethanol. A third phase forming between the water phase & the fuel phase also indicates ethanol.
You might need to check this periodically if you use fuel that is not sold as ethanol free. Formulations for motor fuels do change frequently.
Also, one more thing about 100LL - turbo charged engines don't like it at all. As soon as the turbo kicks in, the motor bogs. This is not an issue on any outboard that I have seen, but I thought it might be interesting to know.
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Yea, Jersey is tough. Cam2 & av gas seem to be about the only options you get in that state for ethanol free. Most of your options can be found here - https://www.pure-gas.org/
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Damnit. This thread has me worried if I just added stabil to the gas at the end of last season or if I actually ran the engine dry...
Guess we will see in a few weeks!
Pretty sure I didn’t, because the west marine article I double checked againstjust said to run stabil added fuel through the engine, not to run it dry.
Guess we will see in a few weeks!
Pretty sure I didn’t, because the west marine article I double checked againstjust said to run stabil added fuel through the engine, not to run it dry.
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I would NEVER put 100LL av gas in an engine not designed to run on it. Outboards are not designed for the high lead content (deposits) and the octane it too high. Read your engine manual and use the recommended fuel octane. High octane fuel eats exhaust valves.
May I recommend that you read the operating manual for your engine? If you don't have one, search the manufacturer's website.
For my outboard, the manufacturer recommends to stop the engine not by hitting the kill switch, but by flipping the ON-OFF lever to OFF. The engine will still run for a minute of two. Then, back the bowl drain screw until fuel no longer drains out. On my engine, that's about a tablespoon of fuel. I use a funnel to catch it and direct it into a glass jar. Sometime in the fall I the summer's drippings as a fire starter back at the house. Since I don't go through an entire tankful of gas in a summer, I add a stabilizer. I have not had a problem.
For my outboard, the manufacturer recommends to stop the engine not by hitting the kill switch, but by flipping the ON-OFF lever to OFF. The engine will still run for a minute of two. Then, back the bowl drain screw until fuel no longer drains out. On my engine, that's about a tablespoon of fuel. I use a funnel to catch it and direct it into a glass jar. Sometime in the fall I the summer's drippings as a fire starter back at the house. Since I don't go through an entire tankful of gas in a summer, I add a stabilizer. I have not had a problem.
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I'm aware of low octane causing pinging & that causing engine damage. I always thought that extra high octane was a waste of money, but otherwise harmless. I'm aware of lean mixtures burning valves. I'm aware of hot fuels burning valves. I am not aware of a relationship between high octane & fuel heat. Can you point me to some info on that?
Thanks,
Jim
Ya know... this leads me to wonder about something. I have noticed that the super cheap $2 LED flashlights with aluminum bodies, will usually corrode at the spot where the copper strip meets the aluminum housing & stop working before they are through their 4th set of batteries. Conversely, the good quality Mag Lights don't do that. I attribute that difference to the guys in California using a better chosen alloy of aluminum compared to the guys in China. Maybe the alloy of the carb body & float bowl makes a similar difference? Maybe cheaper materials act as catalysts for fuel break down????? Are there any chemists here that can shed some light on that possibility?
Actually, I have run motors on straight alcohol before. If you are going to do that, your fuel needs to be 190 proof & you need to check that with a proofhouse hydrometer fairly frequently, as it picks up moisture from the air quickly at that strength. The jets in your carb need to be about twice the normal size when you run alcohol, so your MPG is going to be low. Alcohol is fantastic for promoting rust. If there is any small spec of rust anywhere in your fuel system, the alcohol will make it blossom at an impressive rate. It also eats up the rubber parts in older fuel systems that were made before ethanol was a common ingredient in motor fuels.
I am told that in Brazil, they run all their cars on alcohol for fuel. That has to be tough.
A friend of mine who lives on Anderson Is. in Wash. runs his truck on used cooking oil. I don't know how, but the restaurants on the island call him when they have ample supply of used cooking oil. Crazy.
As for the smell, I was told that if the fuel smells like varnish then it has turned to the dark side. Never had that problem but I did have a clogged carb once. Make that two times on two outboards.
As for the smell, I was told that if the fuel smells like varnish then it has turned to the dark side. Never had that problem but I did have a clogged carb once. Make that two times on two outboards.