Stale petrol

Bedminsterbob

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I have a near full tank of 3 year old fuel, is it best to keep running the engine on it till the tank is empty or keep topping it up with fresh fuel every time I can get a gallon or so in it.
 
Best to ditch it. It will probably have lost most of its octane rating, and therefore will cause the engine to knock, if it starts at all. It really isn't worth the risk.
 
Under no circumstances should you ever use stale two stroke mix on a bonfire.
This is potentially extremely dangerous, with a real risk of an explosive event.

(The bonfire did burn quite well, though :rolleyes:)
 
The tank is 290ltr

Oh, if the engine is running well I think I would use it up as quickly as possible, refilling when maybe 1/3 left.
If it was stored in cool conditions, it could still be ok.
If the engine is difficult to start or knocks, I'd ditch it.
Properly disposing of large amounts of duff petrol is difficult,

.
 
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Oh, if the engine is running well I think I would use it up as quickly as possible, refilling when maybe 1/3 left.
If it was stored in cool conditions, it could still be ok.
Properly disposing of large amounts of duff petrol is difficult,
I think that's what I will have to try, I don't know if adding a Octain booster would help

.
 
I'd drain as much as I could and use it in my car, mixing it 50/50 with good fuel. Perhaps a few tank's worth if I had time. Then top the boat's tank with high octane petrol.
 
Add a couple of bottles of Octane booster and keep adding fresh petrol. Assuming you're not running it hard shouldn't see any problems.
 
And on another note. I run a dual fuel LPG vehicle. Very occasionally I switch it to petrol just to make sure everything is working and it does, perfectly. I have not added petrol in the tank for at least five years, where is the problem?
 
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And on another note. I run a dual fuel LPG vehicle. Very occasionally I switch it to petrol just to make sure everything is working and it does, perfectly. I have not added petrol in the tank for at least five years, where is the problem?
Don't take my word, but do a bit of googling on petrol/gasoline and performance over time. I'm guessing your car engine is quite old? Land Rover V8? Low compression, and unstressed?
 
Don't take my word, but do a bit of googling on petrol/gasoline and performance over time. I'm guessing your car engine is quite old? Land Rover V8? Low compression, and unstressed?

It's old, but I grew out of traffic light competition in my early 20's. Point is that old petrol is not going to trash an engine. Might not generate the 100% you need to create a truly spectacular wake shot but it will still run the engine. Top up, refresh but there is no need to dump it in the oil waste.
 
It's old, but I grew out of traffic light competition in my early 20's. Point is that old petrol is not going to trash an engine. Might not generate the 100% you need to create a truly spectacular wake shot but it will still run the engine. Top up, refresh but there is no need to dump it in the oil waste.
Sorry, bad petrol WILL trash an engine very quickly when you get knock. Marine engines run at much higher duty cycles than automotive, and therefore any knock will quickly trash a piston. Does the OP need to run this risk for £200 of old petrol?
 
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