How Long Does Petrol Last

[JonL]

Hi All

 

I have about 3 litres of petrol left in a 12 litre outboard fuel tank from last year(May time approx).

Will it be alright just to fill up the tank with fresh petrol and therefore have 3/4 new and 1/4 a year old or should I empty the old stuff out first.

 

If I empty it out any suggestions what to do with it ?

 

Cheers

Jon

[Keeping Up]

I'd say (admittedly from experience with lawnmowers and generators, not with outboards) that with only 25% old petrol you would be perfectly OK.

[Paringa]

You will be fine at that age...

 

The only concern with outboards is when they are not used for a while - and that means about a year plus - the petrol can form a gum which causes problems with jets in the carb. If you are leaving the engine for a while just unplug the fuel line on your last journey and let it run until it stops, then you know the carb is as empty as it can be...

[nb Innisfree]

Try to close tank valve and drain the carburettor float chamber before refilling with new mixture.

[magpie patrick]

You will be fine at that age...

 

The only concern with outboards is when they are not used for a while - and that means about a year plus - the petrol can form a gum which causes problems with jets in the carb. If you are leaving the engine for a while just unplug the fuel line on your last journey and let it run until it stops, then you know the carb is as empty as it can be...

 

ah, now Juno's outboard has a problem. After about twenty minutes it stutters badly, sometimes even stalling, and about the only cure is to work the hand fuel pump until it recovers. We've dismissed the fuel tabk not venting (by the simple, but not entirely safe method of running with the fuel cap off) so it's now either dirt (this gum perhaps) or air getting in. As we've cleaned the fuel tank I wonder if the dirt is "gum" in the fuel line.

 

Juno wasn't much used for some time before we bought her

[JonL]

ah, now Juno's outboard has a problem. After about twenty minutes it stutters badly, sometimes even stalling, and about the only cure is to work the hand fuel pump until it recovers. We've dismissed the fuel tabk not venting (by the simple, but not entirely safe method of running with the fuel cap off) so it's now either dirt (this gum perhaps) or air getting in. As we've cleaned the fuel tank I wonder if the dirt is "gum" in the fuel line.

 

Juno wasn't much used for some time before we bought her

 

Got to say I had exactly the same problem with my outboard just after I bought the boat. It seemed that everytime I went out about tens minutes into the trip the engine would splutter and stop, normally exactly when the sandwiches came out

 

Now it turned out that the engine stopping and the sandwiches coming out were actually a related event believe it or not.

 

When the sandwiches came out SWMBO would sit at the back of boat on a seat which forms the lid of the fuel locker.The previous owner had run a new fuel line very badly which meant the slight downward pressure of the seat would squash the fuel line and about 2 mins later when the carb bowl and fuel line emptied the engine would stop.

 

So my advise would be to make sure that something is not restricting the fuel line, otherwise clean the carb out and replace the fuel line.

[nb Innisfree]

Got to say I had exactly the same problem with my outboard just after I bought the boat. It seemed that everytime I went out about tens minutes into the trip the engine would splutter and stop, normally exactly when the sandwiches came out

 

Now it turned out that the engine stopping and the sandwiches coming out were actually a related event believe it or not.

 

When the sandwiches came out SWMBO would sit at the back of boat on a seat which forms the lid of the fuel locker.The previous owner had run a new fuel line very badly which meant the slight downward pressure of the seat would squash the fuel line and about 2 mins later when the carb bowl and fuel line emptied the engine would stop.

 

So my advise would be to make sure that something is not restricting the fuel line, otherwise clean the carb out and replace the fuel line.

 

 

Women, who'd have 'em

[alan_fincher]

Women, who'd have 'em

You are suggesting the previous owner, who made such a bodge of running a new fuel line, was a woman, then ?

 

I do like that story though.

 

EDIT:

 

OK, given the trouble I'm apparently in elsewhere, I can't resist asking......

 

If you want to make petrol last better, would putting sugar in be a helpful way of trying to preserve it ?

Edited March 2, 2011 by alan_fincher

[canaldrifter]

..... not long in my car.

 

tone

[koukouvagia]

There's a load of stuff on the internet about this. The consensus seems to be about 2 – 3 months. I keep a gallon of petrol (properly stored, of course!) on board to start the Kelvin and the stuff I'm using now I bought last June. It's still OK and fired up first go today.

However, I've been caught out once when the engine simply wouldn't start. After cleaning the carburettor, checking the points, changing the plugs etc. I renewed the petrol and all was well.

You can tell that the petrol is going off because the colour gets darker.

[WotEver]

If you want to make petrol last better, would putting sugar in be a helpful way of trying to preserve it ?

Only if you boiled it up, Alan

 

Tony

[alan_fincher]

Well,

 

I'd say based on some of the views offered in this thread, I may well have thrown a perfectly good lawnmower away about a year ago, when just some newer petrol might have sorted it out!

 

There - that should have cheered a few on here up a bit!

 

So, question.....

 

How do people with classic cars that venture out, (say) only once a year or so, manage ?

 

Do they really have to drain all fuel out once they have used them, and put in new the next time they want to ?

 

What happens to the petrol ? (In simple layman's terms, please!...)

[koukouvagia]

Well,

 

I'd say based on some of the views offered in this thread, I may well have thrown a perfectly good lawnmower away about a year ago, when just some newer petrol might have sorted it out!

 

 

Or perhaps you could have used this.

 

No idea whether it works, but I think I'm going to get some.

[LEO]

Well,

 

I'd say based on some of the views offered in this thread, I may well have thrown a perfectly good lawnmower away about a year ago, when just some newer petrol might have sorted it out!

 

There - that should have cheered a few on here up a bit!

 

So, question.....

 

How do people with classic cars that venture out, (say) only once a year or so, manage ?

 

Do they really have to drain all fuel out once they have used them, and put in new the next time they want to ?

 

What happens to the petrol ? (In simple layman's terms, please!...)

 

Hi Alan,

 

Petrol stored in cars for long periods does go off and smells dreadful when it does.

 

I normally run my car's tank down and add some fresh the next year when I want to start it.

 

Both my mowers started first pull when some of last year's petrol was added last weekend - one of them has a Chinese Briggs & Stratton 'lookalike' engine and it is stored out side on the moorings.

 

Hope that helps

 

Mike.

 

Or perhaps you could have used this.

 

No idea whether it works, but I think I'm going to get some.

 

I have tried it, seems Ok but as stated engines seem to manage without it.

 

M