Fuel Additives

[Tony Griffiths]

Tony, I started this thread:-

The other day it was 39 deg C on the road, Fuel tank was 56C, carb 55C, manifold 84C and rad 76C and the 7 didn't like that ........
A drop of 55 deg + between the carb and the venturi bearing in mind the massive butterfly on the FZB22 carb, icing I would think would be rare (at those temperatures). The link to the BP site was an interesting read, where some of the constituent parts of fuel vapourise at 40 deg, could it actually be a case of over rich and "flooding"
It could indeed; when I took the plugs out they were black - so that's another avenue to explore. However, the freezing-cold area around the venture was very real indeed....

[Dave Wortley]

Hello Tony,
Hope the chummy is going well except for the heat problem. If you search “boiling petrol” on here you can see the mods I have done to sort it out. The next alteration was to turn the loop to horizontal instead of vertical as was suggested. Also the rubber wedge mod under the rear of the bonnet.
Regards to Anne. Mike is doing his usual top quality job as mag editor.
Cheers,
Dave.

[keith bashley]

Texaco super unleaded is ethanol free.

[Austin Carr]

According to Texaco, not at all petrol stations.

https://texaco.co.uk/faq

Q. Do Texaco supply fuel containing Ethanol?
Yes. We are required to supply ethanol blended fuel to meet the RTFO (Renewable Transport Fuels Obligation) for petrol (EN228). The specification allows for up to 5% Ethanol (E5) and we currently supply this in the majority of our 95 unleaded grade. In addition we now also supply E5 (contains up to 5% bio ethanol) 97 Octane Super Unleaded grade to much of the country.

[Douglas Alderson]

Esso Supreme + is ethanol free according to their web site https://www.esso.co.uk/fuels-faqs

The majority of unleaded 95 Octane petrol sold in the UK contains up to 5% ethanol as required under the Government’s Renewable Transport Fuels Obligation (RTFO).

There is currently no requirement for renewable fuel (such as ethanol) to be present in super unleaded (97 grade petrol).

Esso super unleaded petrol (Synergy Supreme+ Unleaded 97) is ethanol free (except in Devon, Cornwall, the Teesside area and Scotland). We would therefore advise anyone who has concerns about the presence of ethanol in petrol to use Synergy Supreme+ – providing they do not fill up in Devon or Cornwall, the Teesside area or Scotland.

[Tony Griffiths]

Hello Tony, Hope the chummy is going well except for the heat problem. If you search “boiling petrol” on here you can see the mods I have done to sort it out. The next alteration was to turn the loop to horizontal instead of vertical as was suggested. Also the rubber wedge mod under the rear of the bonnet. Regards to Anne. Mike is doing his usual top quality job as mag editor. Cheers, Dave.
Hi Dave, thanks for your message. The Chummy is going very well indeed and starts from cold on the second swing of the handle - Mike was also rather surprised at the way it fled from his Appia on the way back from the Litton VSCC lunchtime meeting a few weeks ago. However, the old problem still exists, though it's surprisingly inconsistent, e.g. I went for a run the other evening and, within a few miles, it started spluttering and would only take part throttle. Having refuelled at Calver with 10 litres, the misfire cleared almost immediately and it ran up through Stoney Middleton Dale in top gear and down the straight into Wardlow Mires at an indicated 60. It then climbed the steep hill out of Wardlow in top - the last section, as it crested the rise, dropping to just 15 m.p.h. in top at full throttle and running cleanly. Work that one out!  So, I've just bought a digital temperature gauge and plan to monitor some parameters (various temperature readings around the carb for example) to see if I can isolate a particular problem. I'll let you know when I have some results - if not answers....

[Mark McKibbin]

Tony,
It sounds like icing to me as it only happened early in the trip, later on the heat would have soaked to the manifold from the block.

[Tony Griffiths]

Hi Mark, It was my suspicion, too. However, a mid-run rest and "heat soak" failed to cure it - it was only after a refuelling that it stopped. The inlet manifold has no hot spot and does get "freezing" cold - though how freezing I'll find out when I rig a thermocouple to it.

[Alan]

I’ve experienced the new fuel thing as well, in my RL. I put it down to the new fuel being cooler than that already in the tank and therefore less likely to vaporise with the heat under the bonnet. Interestingly, it was a long journey and the problem returned as the fuel in the tank heated up.

[Mark McKibbin]

Maybe someone should temporary affix some of that silver firewall insulation on the firewall side of the fuel tank and see if it keeps the fuel temp down in the tank. Assuming this problem is only happening in firewall mounted tanks.