Opinions on fuel stabiliser?

Tom_95

New member
With me driving the 504 less and less lately, I'm finding that I only fill it up every 6 months or so. With this, I'm getting missing under heavy acceleration, difficult hot starting... Blah blah blah. All of these issues disappear after filling the car up with fresh fuel, so I'm considering starting to use a fuel stabiliser to hopefully negate these problems.

My question is, does anyone have any reasons why I shouldn't be using stabiliser?
 
While AVGAS has a use by date and pilots are wary of drums at small fields a 504 should not be sensitive to old fuel in a tank. I certainly have no issue with drum fuel that can be a couple of years old. The common cause of fuel caused missing is water in the fuel.
 

COL

Alpine A110
With me driving the 504 less and less lately, I'm finding that I only fill it up every 6 months or so. With this, I'm getting missing under heavy acceleration, difficult hot starting... Blah blah blah. All of these issues disappear after filling the car up with fresh fuel, so I'm considering starting to use a fuel stabiliser to hopefully negate these problems.

My question is, does anyone have any reasons why I shouldn't be using stabiliser?
What grade of fuel are you feeding your 504 on?

If you use it your 504 only a couple of times a year I would be putting in the highest grade of fuel you can lay your hands on, e.g. 98 or a minimum of 95.

I use my R12 irregularly and run 95 in it, after a bit of cranking so that the mechanical fuel pump can fill the carby with fuel in starts and runs fine.
 

COL

Alpine A110
While AVGAS has a use by date and pilots are wary of drums at small fields a 504 should not be sensitive to old fuel in a tank. I certainly have no issue with drum fuel that can be a couple of years old. The common cause of fuel caused missing is water in the fuel.
Just a friendly reminder that it is illegal to use leaded fuels on the roads of Australia.
 
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driven

1000+ Posts
Fill fuel tank if sitting. Less condensation forms inside.
Experiment
Clear glass bottle with screw cap. Make pinhole in cap.
Leave in sunny spot, bottle will fill with water from expansion / contraction of air inside bottle over months.
Bush mechanic fix, add capful of metho, water then becomes miscible with petrol
Just the tonic for your 504 :)
 
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COL

Alpine A110
Fill fuel tank if sitting. Less condensation forms inside.
Experiment
Clear glass bottle with screw cap. Make pinhole in cap.
Leave in sunny spot, bottle will fill with water from expansion / contraction of air inside bottle over months.
Bush mechanic fix, add capful of metho, water then becomes miscible with petrol
Just the tonic for your 504 :)
Another method is to keep the tank full which will also stop the condensation forming.
 

COL

Alpine A110
Which means what? That's what I love about the internet, share a bit of experience and there's always the smart arse comment.
It is not a smart arse comment. Avgas to the best of my knowledge is a leaded fuel so it makes it illegal to use on the public roads of Australia. Avgas was fine last century but not this century
 

85Fuego

Member
Use fuel stabiliser on both the lawn mower fuel and the infrequently driven Fuego.
Apart from the cranking to fill carby bowl, drives well with no hesitation.
I also chuck metho in once a year....

Anecdotally the higher the RON the more volatile the fuel additives are.
I use 95.
 

JohnW

Too many posts!
I'd suggest a better solution is to use the car more. There are many issues that emerge if cars aren't run regularly. I know it is easy to be wise.... Certainly my solution would simply be to fill the car more often so it sits with minimum air gap in the tank.
 

Beano

1000+ Posts
I know nothing about stabilizer, but have never heard problems with it. However ( and pardon me stating the obvious) it'd be best to run the car till tank almost empty, before filling with 98 octane. Especially if your 504 is so old that it has a metal tank. The problems may be caused by rust and crud in the bottom....or at least contributed to partially.
Tom, are you 100% certain that the missing & poor hot starting are from the old fuel, and not simply because you have used the car for a little while by the time you put in new fuel ?
When I was starting my 505 for the first time in a while, I kept a screwdriver handy and whipped off the air cleaner connection to the carby top and poured half a cup of fuel into the carby throat. Otherwise, I found it mentally painful to hear the car cranking over to pump the fuel through.
 

pgti6

1000+ Posts
My race car has been in storage since late lat year and until this week not been started.
On advice from a PCCV member I purchased some Penrite Petrol Fuel Stabiliser adding the recommended amount into the tank (25ml per 20 litres).
I’ve no idea how effective it’ll be but if it prevents gums and waxes forming on the lift or fuel pumps or clogging the injectors I think it’s well worth the $17 outlay.
 

andrewj

Member
Hi Tom,

I would second JohnW's suggestion. Take the car for a good run every few months or so.

I am currently going through the process of bringing a similar era car back to life after many years of under use, and am finding now end of minor but niggly issues associated with under use. i.e. yellow slime coming out of the exhaust, horrible smelling oil (no crank case ventilation on this one!), a sticky valve, intermittent slow fuel leaks from the fuel pump, jelly in the carbies, dribbly rocker cover gaskets, stiff gear change - the list goes on. All these are one by one improving or disappearing with more regular use. But I thinking that are regular run to keep everything dry, lubricated and fresh is a whole lot less stress than dealing with the symptoms of under use.

Cheers,
Andrew
 

JohnW

Too many posts!
I know nothing about stabilizer, but have never heard problems with it. However ( and pardon me stating the obvious) it'd be best to run the car till tank almost empty, before filling with 98 octane. Especially if your 504 is so old that it has a metal tank. The problems may be caused by rust and crud in the bottom....or at least contributed to partially.
Tom, are you 100% certain that the missing & poor hot starting are from the old fuel, and not simply because you have used the car for a little while by the time you put in new fuel ?
When I was starting my 505 for the first time in a while, I kept a screwdriver handy and whipped off the air cleaner connection to the carby top and poured half a cup of fuel into the carby throat. Otherwise, I found it mentally painful to hear the car cranking over to pump the fuel through.
Yes, why use a starter motor as a fuel pump? :) Can you get fuel pumps "avec levier" for those Peugeot engines? It's one good solution to the intermittent use matter.
 

JohnW

Too many posts!
Hi Tom,

I would second JohnW's suggestion. Take the car for a good run every few months or so.

I am currently going through the process of bringing a similar era car back to life after many years of under use, and am finding now end of minor but niggly issues associated with under use. i.e. yellow slime coming out of the exhaust, horrible smelling oil (no crank case ventilation on this one!), a sticky valve, intermittent slow fuel leaks from the fuel pump, jelly in the carbies, dribbly rocker cover gaskets, stiff gear change - the list goes on. All these are one by one improving or disappearing with more regular use. But I thinking that are regular run to keep everything dry, lubricated and fresh is a whole lot less stress than dealing with the symptoms of under use.

Cheers,
Andrew
I meant every few weeks, I'd add!
 

garryw

New member
I have a couple of light planes (as well as pugs, so I'm not completely crazy!). I can use Avgas or 98 in both planes. Modern Avgas has less lead than in the past, but I'm not sure what it is now. I can leave Avgas in the planes for at least a year and it's fine. Throw away the 98 at 3 months. Old 98 makes the engines in the planes run rough and overheat if old (preign?). Remember the aircraft engine fuel and electrical system is VERY simple. No fancy electronic to retard on poor fuel etc etc. Just runs bad and sometimes stops. Makes life interesting. Our choice is usually 98 and Avgas if you are not flying very much. Easy to get Avgas. Most country airports you just drive in and fill up! I didn't tell you that!!
Garry
 

blacklotus99

New member
Fuel stabiliser is very much a half way measure in my experience. It might work after a short period of sitting but I wouldn't count on it.
The issues that Andrew is talking about are very common along with starting problems, misfires etc. I have seen this mostly on British bikes with Amal carbs. 4/5 times these bikes don't start is because of old fuel and the jets and needle blocked so the carbs have to be gone through. Modern unleaded fuels have all kinds of crap in them including ethanol in many and lots of detergent in 98. Those fuels aren't designed for carbys on any car or bike and avgas can't be used anymore, although leaded avgas did last a long time on the shelf or in the vehicle.

I recently recommissioned a 205 that had been sitting for years with fuel in the tank. The fuel had turned to varnish and seized the fuel pump and sender. So it was tank out to be cleaned, new pump, most of the fuel lines replaced and the injectors cleaned etc. All because someone left old fuel in the tank.

If I leave any petrol vehicle sitting for more than two weeks I drain the tank and I only ever use the minimum amount of fresh fuel required from a high quality source. Its also a good idea to use flashlube or similar to keep the pump lubricated and it also stops carbon buildup on throttles etc. If you want more octane use booster. Drain the carby bowl or run it dry at the same time you drain the tank or the fuel will consume all the seals in the carby over time. The other option is to get a diesel, and then you get lots of different problems!
 
My understanding (or misunderstanding) is as follows:

The lower the RON, the less stable the fuel is over time. So, for an underused vehicle, use a higher (95 or 98) fuel.

Fuel stabilisers work & higher rates work for longer times

Of course the fuel in your tank might be fine but the carby jets be clogged by the residues of vaporisation. If it can be at all started, then the situation should be resolved by the addition of a fuel system cleaner & running the engine.
 
The additives in modern fuel are at least a part of the issue, as others have noted

I had a good example of this a while ago in Lurch ( Haflinger ) which has had an electric pump fitted. Petrol was leaking and had been doing so for a while, so I went in pursuit.

The giveaway was the stalactites of grey/white waxy goop hanging from the pump connections, left there after petrol had evaporated

It hadn't taken long

Am now worried about how Reg (4CV) will go when fired up, as he has been having a prolonged sook in garage. Because of the number of infrequently used petrol engines I have and one oldi I have to resuscitate I have now invested in ultrasonic cleaner

Analogous experience with lawnmower, which failed to progress after winter off. Carburettor gunked up with crud. I now use the old Brit motorbike trick - switch off the tap and run the motor dry, so nothing left in float bowl.

Andrew
 

jaahn

1000+ Posts
Hi :confused:
I now use fuel stabiliser in the fuel for my old bikes and small engines. I got sick of having to clean out the gum and crud that settles in the carbys and pumps. I always used 98 anyway but I do not believe it is the additives but the poorer quality of the fuel that is being imported into Australia in the recent years. The base fuel is not as clean.
It seems to work for me and has made life a bit easier. If I had an old car I would use it in that too. While it is easier to say just use it more often and drain the tank and bla bla, not everyone wants to spend their leisure time working on boreing jobs just for few hours pleasure. I have played with that sort of stuff for 50 years and am happy to just put a $20 bottle of magic in if necessary. They use it in other countries routinely for winter storage of engines, we have just been spoilt here !
Never use E10 fuel in them as I have some experience back in the '80s of how bad that can be for some carbie parts and soft bits. I do use E10 in my new car by the way. I have recently had an experience of my old 2000 diesel suffering leaking from pump gaskets due to 'poor' fuel from a cheap place that was cured by using better fuel since.
Jaahn
 
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