Fuel additives/stabilizer?

[1owner69Elan]

When I was at Dave Vegher's shop this weekend he recommended that I consider using a fuel stabilizer or purer race gas to avoid deposits/gum in the Webers. This is because I don't necessarily drive the car often and because of the ambient evaporation of fuel in the Webers while sitting and during heat soak after driving. Dave says the current formulations of pump gas (at least in California) can leave gum/varnish from evaporation. Says he encounters Webers that are a mess from our pump gas and all gummed up.

I don't need the race gas for performance or pinging issues (another topic) and it's expensive, so will look at using the additive.

Dave uses "Seafoam" gas additive especially when cars are infrequently driven.

When my newly built engine was stored for 15 months after its dyno session on pump gas, we finished by flushing the pump gas out by running pure race gas through the system. Later when starting up, no problems and the carbs appear to still be whistle clean.

[The Veg]

Seafoam is decent stuff.

[prezoom]

Seafood Fogger works well for long term storage.

[StressCraxx]

Drive it and your fuel won't go stale.

[Certified Lotus]

I use ?Carb Defender? from Joe Gibbs Racing. The shop that built my engine strongly recommended.

[denicholls2]

The concern is a real one, modern gasoline has been legislated into garbage compared to what these cars were weaned on, but there's a less-expensive (and potentially more effective) alternative that is particularly simple if you have an electric fuel pump: Shut off the fuel supply and let the bowls run dry when you park it. If it's going to sit a long time, pump the tank dry too and burn it in your daily driver.

I use this strategy for lawnmowers and snowblowers, devices that experience annual storage cycles. In diagnosing my own and others' starting and fuel supply problems, I've seen a lot of tar buildup, about 1/8" thick on the float of one snowblower carb. That wreaks havoc on the float level and clogs the carb's arteries too. Problem solved by not leaving any fuel in the bowl to evaporate.

Note that stabilizers claim to help prevent this buildup, but recommended shelf life of stabilized gasoline is only 6-8 months.

[JonB]

That's an interesting point, denicolls2. I get the same sort of issue on my chainsaw, which does not get used very often. The petrol / 2 stroke oil mix is kept in a sealed bottle, though, and when I attempt to start it with whatever is left in the chainsaw's tank, it is always difficult. Top it off with the (admittedly old, but kept in the sealed container) fuel and it starts much easier.

[vincereynard]

The concern is a real one, modern gasoline has been legislated into garbage compared to what these cars were weaned on, but there's a less-expensive (and potentially more effective) alternative that is particularly simple if you have an electric fuel pump: Shut off the fuel supply and let the bowls run dry when you park it. If it's going to sit a long time, pump the tank dry too and burn it in your daily driver.

+1
That's two of the reasons I went electric. Stop by the garage and switch the pump off.
By the time the garage has been opened and the car inside its starting to spit with low fuel.

Draining the +2 tank is distinctly awkward otherwise. With an electric pump its a piece of cake.

Forgetting to turn it on however ...............

[alan.barker]

Drive it and your fuel won't go stale.

+1 I fill up with 98 when i can find it
Alan

[denicholls2]

Gas over the pond may differ, here octane ratings are typically raised by adding ethanol. That is not a solution to the deposit problem, rather it seems to exacerbate it (though I am not a chemist).

It does seem logical that alcohol as a different solvent from gasoline would dissolve nastier solids that would then need somewhere to go when it evaporates.