Fuel Additives

[bob46320]

Note 2 - need to build garage extension for spare parts I will never use.

[Reckless Rat]

Good point. It's probably a doer-upper but there's no paperwork. Anyway, if it keeps mine going for a bit longer I'll be happy. I still have a 2CV alternator and a Dyane front grille on the shelf too...

["Slack Alice" Simon]

Went to the Club spares shed with a long list.   The plan is to turn the bits of engine in the shed into a spare each for the cars, one to sell, and enough bits for another one "just in case".

Which will tidy up the shed a bit.

Got mightily lost on the way - I try and use the most obscure roads - which I did, but had to retrace my way twice.   I rely on my faulty sense of direction and paper maps which I don't stop to look at.

Only about 70 mile round trip, lovely in the sunshine.   The shed had just about everything I wanted, much head scratching - "are you sure you want THREE sumps?" - and the lightness of the wallet balanced the weight of the spares on the way back.

Today: Gardening.  

["Slack Alice" Simon]

Drat! That last one should have been in "What did you do ….."


On the subject of fuels, which we are, sort of:   I have been fairly casual about the debate about old fuel.   But the Cambridge doesn't get used much, and I drain year old fuel out and put a bit of new in, if it is that long between runs.

I decided to try the old fuel, by now probably 18 months old, in the lawnmower.   Lawnmower has been tolerant up to now, not minding if it is running on  two stroke left over from the outboard, for instance.

With the old fuel from "Alice" the mower was firing every other stroke or so, and eventually stopped.   It has a suction operated fuel pump, and I think the erratic running has blown the seals in it, because now the engine appears to be ingesting fuel directly from the tank, bypassing the carb.

Fortunately it is convertible to gravity feed, but I will be a little more careful using old fuel from now on.

[Ron Hayhurst]

Just picked up this thread and was surprised to learn how high a temperature had been found in scuttle tanks.
Some time ago, when there was discussion about the more volatile components of today's petrol, I did a little experiment - all in the open air, away from any sources of ignition! I heated a pan of water indoors to about 80C. Back outdoors, I poured some petrol into a bean can and popped in a thermometer. When the can was immersed in the pan of hot water the petrol soon boiled at a mere 40C!!!! It only boiled for a short time and most of the petrol remained in the can. Such is the volatility! Maybe others would care to do a repeat to see if the same is found today.

[Paul N-M]

Just picked up this thread and was surprised to learn how high a temperature had been found in scuttle tanks.
Some time ago, when there was discussion about the more volatile components of today's petrol, I did a little experiment - all in the open air, away from any sources of ignition! I heated a pan of water indoors to about 80C. Back outdoors, I poured some petrol into a bean can and popped in a thermometer. When the can was immersed in the pan of hot water the petrol soon boiled at a mere 40C!!!! It only boiled for a short time and most of the petrol remained in the can. Such is the volatility! Maybe others would care to do a repeat to see if the same is found today.

Unsupervised school chem lab stuff! What jolly japes.

Interesting though.

Paul N-M

[Mark McKibbin]

Just to add fuel to the fire, here is what BP thinks about it.

https://www.bp.com/content/dam/bp-countr...ngines.pdf

[Tony Griffiths]

Carb icing?
Could we, just possibly, be barking up the wrong tree here? Probably not, but the other day, when it was both hot and humid and the engine would not take full thottle and misfired. I stopped to check - the SU carb on my Chummy has no hot spot (4-branch exhaust) and around the area of the venturi was ice cold with copious amounts of condensed water. The float bowl was warm, but not hot. Now, as I was once assured by a flight instructor telling me about induction icing problems, "It's always winter inside a carb" - and even at temperatures exceeding 30 deg C on humid days the drop in temperature between inlet and venturi can lead to icing. So, when it stops raining, I'm going to try the 1% to 2%  recommended of this: https://www.amazon.co.uk/gp/product/B006...UTF8&psc=1
Incidently, many pilots have lost the plot when, suffering from icing, they've switched to hot air and despaired as the engine ran even more roughly as the ice melted. In a panic they turn hot air off, only for the engine to stop and refuse to restart. At least we can park at the side of the road....

[bob46320]

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"

[dickie65]

I have suffered from carb icing with a downdraft Zenith on the Type 65.
I taped a electronic themometer sensor to the carb went for a run and the temp dropped well below freezing.
I now run a SU semi downdraft.
The Type 65 / Nippy has a hot spot to help stop carb icing.