Fuel Additives

[IainM]

Does anyone have any experience of fuel treatments which would slow down, stop or even reverse the degradation of fuel if, inevitably, it is left lying around for long periods of time?

I have heard of an American product, PRI-G, which makes great claims. Does anyone know of it? Is it available in the UK?

IainM

[RickUK]

Hi Iain - I try not to leave old fuel in tanks, but as you say, inevitably some hangs around. I find that if a motor is healthy, it will start on six month old fuel at least, and you can perk old fuel up by adding some fresh. It is the aromatics part of the fuel which evaporates over time.
The worst problem I have seen with motors not used for a very long time is that all the petrol evaporates, and leaves the oil element of the mix as a hard residue in the tank. Rick

[Donald A]

Interesting topic - Bill Mitchell of Home Marine (at Emsworth Yacht Harbour, maintaining exclusively outboards for 30 years) has said that modern British lead free petrol burns/scores the cylinder walls at high temperatures, as against the old leaded 4 star. Something to do with British petrol having ethanol in it, whereas American petrol doesn't. He suggested adding one of the additives which are fairly easily available - Quicksilver Gasoline Stabilizer, or Briggs and Stratton Fuel Fit or Castrol Valvemaster lead replacement additive. His hobby is tuning rally car engines.
I haven't seen any data proving any of this one way or another - but I suppose it's the sort of topic where it's not in the interests of the oil companies to publicise/fund any work on it.
Anyone out there in the industry with some non attributable information on this?
Regards
Donald A

[IainM]

Thanks for the comments. Try Googling Pri-g. The universal panacea!

[IainM]

PS No I am not connected with the product in any way - just intrigued.

[Andrew Craig-Bennett]

I have noticed that if I loosen the cap on my very standard geen plastic 5 litre petrol container, in warm weather, there is an audible "shhh" as the pressure inside equalises with the atmosphere.

No similar effect with the Seagull's (brass) tank, which makes me tink it may be less gas-tight.

I suspect that light fractions evaporate much faster out of the Seagull tank.

[John@sos]

Bet you are right!

John
SOS

[Colin]

Does anyone have any experience of fuel treatments which would slow down, stop or even reverse the degradation of fuel if, inevitably, it is left lying around for long periods of time?

I have used a similar product in my chain saw when I left it stored for a summer. It did work and certainly seemed to prevent the fuel from varnishing and noticeably so in the carburetor bowl. However, I realized it was cheaper to discard a quart or so of fuel and drain the carb, than buy the additive. Consequently I've never used it since.

Colin.

[CatiGull]

I drain the flock for winter, including carb bowls, and also do a quick rinse of the tanks with fresh petrol (no oil) in the spring to wash residual oil and dirt .

I also dont make up petrol mix in the cans anymore - instead, I have a graduated container and mix up a liter of the correct mix as needed on the boat.

Some of my engines run best on 10:1, and some are 20:1 so I dont end up throwing out mixed petrol I dont need this way...it also never gets stale since I use it in the grass mower at home as well..