Preventing Stale Gasoline

[Sehansen]

Hi - I would be interested in your thoughts/experience on preventing and dealing with gasoline that has gone "bad". I have a 25hp Honda outboard on my dinghy that doesn't get used very often. This fall I went to start it up and it wouldn't run or idle. After having a mechanic tear down the engine and carbs it appears to have been caused by old gas that had been in the tank way too long. He isnstill having problems getting the carbs totally clean (still faltering at mid speed) and after several hundred dollars of labor I want to make sure it doesn't happen again. How often do you change out your gasoline? Do you recommend or avoid additives? Are premium grades any better than standard octaves?

[Khagan1227]

I put Sta-Bil gasoline stabilizer in all of my tanks if I don't run the gas out of them before winter hits.

BTW, Higher octanes generally don't do much for engines that can use lower octanes. Higher octanes are usually used in high performance engines and older engines to reduce/eliminate "engine knock". Save your money, buy the gas that is recommended for the engine.

[zeehag]

gasoline has a shelf li8fe of 6 months. i wouldnot count on sta-bil to prolong that. varnish is similar in smell to old gas. mix for outboards is a 2 month duration. diesel wins all--has no shelf life. add your biocides and keep on keeping on.... 4 yrs later mine is still good. the gasoline shelf life source is a man who worked as a salesman for a large chemical co and sold tetra ethyl lead to the oil companies. leaded gas lasted longer than our non leaded. made gasoline cheaper to make also.

[Chief Engineer]

You can tear down the carb yourself.

Get a gallon can of Carb cleaner. It is like a gallon Paint Can with a small basket inside. Do not put plastic parts in it. Blow parts clean with brake cleaner...not carburetor cleaner and blow out orifices with compressed air.

Wear eye protection

[O.C.Diver]

I used to run charter boats with outboards. This was back when they were all 2 cycle and you mixed oil with your gas when filling the fuel tank. I was concerned about the gas in the carburetors evaporating when the boat sat for long periods and the carb being internally coated with 2 cycle oil making it really hard to start. My solution was to disconnect the gas tank fuel line from the motor while the engine was running and run the engine until it quit. Never had a problem with fuel or oil.

I have an aluminum 16' fishing boat with a 25 year old 6 HP Merc on it. Every year I use the boat I always start with fresh gas. At the end of each season, I burn whats left in the fuel tank in my lawn tractor. By running the engine till it quits, I have never had a fuel problem.

I'm getting ready to own my first dingy. My plan regarding fuel is mix smaller quantities and dump any fuel that's more than 6 months old. Fuel is really insignificant in cost for a small outboard compared to a repair bill. Instead of trying to extend it's life make sure your gas is always young.

One final thought: I'm not sure how running the engine out of fuel would effect fuel injected out boards.

Ted

[ShaunJ]

I know many people who do it your way without any problems, and I know a few people who say, "when you run a 2 stroke engine out of fuel you also take away the lubricant" I am not sure who is right. If you run a 2 stroke out of fuel, what is lubricating the engine? When you restart it, do we just hope it gets enough lube from the new fuel to lube it?........ I just don't know which way is right.
I can say one thing, you wont have any fuel problems with the "run it out of fuel each time you use it."

[O.C.Diver]

Originally Posted by ShaunJ

I know many people who do it your way without any problems, and I know a few people who say, "when you run a 2 stroke engine out of fuel you also take away the lubricant" I am not sure who is right. If you run a 2 stroke out of fuel, what is lubricating the engine? When you restart it, do we just hope it gets enough lube from the new fuel to lube it?........ I just don't know which way is right.
I can say one thing, you wont have any fuel problems with the "run it out of fuel each time you use it."

The engine only runs for a couple of seconds without fuel. Also, the fuel oil ration is set for the worst case scenario. Outboards require the highest ratio of oil at peak RPM. At idle they require much less oil lubrication. The only oil injected outboard I ever owned, had a 50:1 ratio at full speed and something like 150:1 at idle. For a fixed ratio outboard there will be way more than enough lubricant. At least that's been my experience for the last 25 years.

Ted

[Bash]

If there's ever a point where you think you won't be running the outboard for a month or more, take the fuel tank up to the parking lot and pour it into an automobile. (Preferably your own.)

[Cormorant]

If you're ever worried about the cylinders being lubricated during a period of layup -- after running the engine with gas line detached -- just remove your spark plugs and spray in some fogging oil. Then slowly pull the starter rope a few times (with plugs still out) to distribute the oil evenly over the whole cylinder. Then replace plugs. Prevents corrosion, and makes your first springtime start-up a breeze (and a bit smoky for the first few seconds).

[Mule]

I spent some time with a guy that filters fuel and he gave me some insight into his business. He said that since ethanol his business has been centered more on emptying gas tanks and disposing of the gas separated from the ethanol than filtering the infected diesel. There is no process other than disposal for gasoline that is waterlogged from separation and asorbtion of H20.

Please tolerate my small rant. Ethanol is fuel is nothing more than a political payoff to the corn states, and by the time it gets distributed there are more BTU's spent than it saves. Poorer fuel economy and it is damaging to engines. There is a bump from 10% to 15% scheduled soon and it is going to play hell with our engines, cars, trucks, marine...All.

So I would say the first thing to do for gas powered engines used sporadically is to find a source of gas that is only gas. Second treat that gas with stabil or some other additive, get rid of your gas when you see you will not be using it for months on end, before or after but DO NOT RUN IT. Lastly the fogging process sounds great to me.

[GordMay]

Originally Posted by Mule

... Please tolerate my small rant. Ethanol is fuel is nothing more than a political payoff to the corn states, and by the time it gets distributed there are more BTU's spent than it saves. Poorer fuel economy and it is damaging to engines...

Interesting concept: turning good food into poor fuel.
Brings to mind the diametric: “edible oil products”.

[Chief Engineer]

Even the envionmentalists finally realized that this is a bad idea.

Are the ethanol subsidies going to stop? Nope.

They should just make cheap moonshine....for those of you that imbibe.

Maryland still has emissions inspection stations which are a cash cow...

Good luck finding non-ethanol fuel

[Sehansen]

Thanks everyone for the excellent tips - wish I had found this forum a few months ago.

[O.C.Diver]

Originally Posted by Chief Engineer

Even the envionmentalists finally realized that this is a bad idea.

Are the ethanol subsidies going to stop? Nope.

They should just make cheap moonshine....for those of you that imbibe.

Maryland still has emissions inspection stations which are a cash cow...

Good luck finding non-ethanol fuel

Thankfully not down here on the Eastern Shore. Never did understand why we got spared on that nonsense.

Ted

[stensmo]

Usually outboards will run fine using stale gas They just wont start. If you have two tanks, start the outboard using fresh gas and then switch to the stale one.