Old petrol

mixyblob · 01 April 2016, 17:56

Just realised I've got 10 ltrs of unleaded in a can which is 6-7 months old.
Is it ok to use this in my 2st 25 Mariner? or just add a bit to each tank of fresh fuel.

Fender · 01 April 2016, 18:03

I'd mix it with a little fresh, will be fine

The Gurnard · 01 April 2016, 18:06

I have had three great days using my 3.3hp two stroke mariner this year.. on fuel I mixed 50:1 and have kept since last September. Ran a sweet as always.. its up to you what you do

jeffstevens763@g · 01 April 2016, 18:30

Stablise it if not sure but should be ok still I have only had trouble after 12 months it was easy when I had a petrol car it got put in there to get home

beerbelly · 01 April 2016, 19:00

it will be fine

Fenlander · 01 April 2016, 19:11

I've never had an outboard not start or play up on fuel up to a year old. However it may not run at it's best so I try and mix 50/50 with new and get it used that way.

Must admit one advantage to me with moving to 4-stroke is that we run two petrol cars here and I can put left over fuel in the cars after each trip meaning the outboard is using new fuel all the time.

beamishken · 01 April 2016, 22:54

I was told the part of the fuel that degrades is the lighter more volatile part which assists cold starting
So my theory is if it starts it's fine

mixyblob · 02 April 2016, 11:48

Thanks for your replies gents, I think I'll just add a bit of the old fuel to each tank of fresh.
Wasn't sure if the old petrol could damage the engine but you have put my mind at ease thanks.
Jim

Sutty · 02 April 2016, 17:13

Are you sure that boating is for you if you are bothering about £10 of fuel

willk · 02 April 2016, 18:09

Quote:

Originally Posted by Sutty

Are you sure that boating is for you if you are bothering about £10 of fuel

It's the age of the fuel that the OP is concerned about - not the volume. The answers apply just as much to the 300L of petrol you probably have lying in your own tank!

The OP may have no conventional way to get rid of unusable petrol (if such exists

) - diesel car, electric garden tools...

Stigomery · 05 April 2016, 11:00

I don't want to derail this conversation too much so apologies to OP if I do... but I have related question that bugs me somewhat... there is lots of talk of "old fuel" per this thread and various issues with engines, carbs, injectors, etc. associated with said fuel.

Now I might be in the minority here, but I have 4 stroke lawnmowers that have run for 15+ years without so much as an oil change never mind the crap petrol that has been thrown in them over the years. They have always started first pull and never given me a moment of trouble.... why is that OBEs seem troubled with "old fuel" and other issues? Or is that just my impression. Is it simply down the abuse they suffer on the open sea? And why such concern about "age of fuel" etc. when this has never (noticeably) affected any of my "land engines"? Perhaps it's a 2-stroke vs 4-stroke thing?

jeffstevens763@g · 05 April 2016, 11:47

agree but bit different breaking down on your front lawn than out at sea all about managing the risks, but treatments say it will last for 12 months so end of season treat.
i still use it for the lawn mower etc and top up when i go out in the boat of course you can run it right down before storing.

cheers

beamishken · 05 April 2016, 12:08

Stigomery In 40 years of boating I've never had a problem with old fuel even in 30 years in the motor trade I never had a problem with old fuel even old cars we dragged out of barns and garages managed to Burst into life without changing fuel (Assuming no other problems)
I'd suspect people who have had issues with old fuel ( last seasons) have actually had a problem with a bit of dirt in there carb or solidified oil left when the petrol has evaporated & after messing around changing fuel etc the engine has run but quite likely had they persevered the engine would have run anyway.
I'd imagine there is some substance in the myth that old fuel is no good in that in certain circumstances the fuel can deteriorate but I'm my opinion they are few and far between.
As I said earlier I was told it was the more volatile portion or the fuel that degrades so if it starts initially then your probably going to be fine.
No doubt I'll be shot down in flames for daring to state that old fuel problems are somewhat of an urban myth but that's my experience & belief

willk · 05 April 2016, 12:50

Quote:

Originally Posted by beamishken

No doubt I'll be shot down in flames for daring to state that old fuel problems are somewhat of an urban myth but that's my experience & belief

...it's an explosive topic ATM.

dave3235 · 05 April 2016, 13:10

Quote:

Originally Posted by mixyblob

Thanks for your replies gents, I think I'll just add a bit of the old fuel to each tank of fresh.
Wasn't sure if the old petrol could damage the engine but you have put my mind at ease thanks.
Jim

Hi all

I had herd that the 2 stroke oil if premix starts to seperate,also moisture is atracted to petrol.Stored,fill your tank to brim will eliminate the moisture side of things or lesson it.

9D280 · 05 April 2016, 13:35

I have happily run a premix 2- stroke on premix petrol we later realiaed was 8 years old..... OK, it smoked a bit as I suspect the relative evaporation of the fuel & the TCW3 had turned it from 50:1 to something more akin to "Seagull mix" but we had a good day's boating on that can... and the engine started 2nd pull.

HDAV · 05 April 2016, 16:41

I have run old fuel in all manner of things from mowers to outboards and all sorts between and not had an issue but that doesn't mean it's a good idea....

chipko · 05 April 2016, 17:00

Although I've never had a problem, I think the modern unleaded ethanol-mix fuels are far more prone to absorbing water vapour and separation than the old leaded fuels.
As I do not winterize (fire up monthly usually if I remember) or drain down the fuel systems after each use I now stabilize all fuel at point of purchase for peace of mind. Over the season I use Quicksilver Quickare and over winter Quicksilver Quickstore.....cost is negligible over the year. Probably overkill as always use fresh fuel with any leftover going into car/mowers etc. and fuel left in the lines, carbs, injectors etc. is already pre-treated anyway.

steco1958 · 06 April 2016, 08:46

Quote:

Originally Posted by Stigomery

I don't want to derail this conversation too much so apologies to OP if I do... but I have related question that bugs me somewhat... there is lots of talk of "old fuel" per this thread and various issues with engines, carbs, injectors, etc. associated with said fuel.

Now I might be in the minority here, but I have 4 stroke lawnmowers that have run for 15+ years without so much as an oil change never mind the crap petrol that has been thrown in them over the years. They have always started first pull and never given me a moment of trouble.... why is that OBEs seem troubled with "old fuel" and other issues? Or is that just my impression. Is it simply down the abuse they suffer on the open sea? And why such concern about "age of fuel" etc. when this has never (noticeably) affected any of my "land engines"? Perhaps it's a 2-stroke vs 4-stroke thing?

I'm with you on this, I'm considering a 1st service on my lawnmower, 12 years old