Wow! Good job Mad Farmer. My bad for assuming again.
Seems they start/warm up on gasoline, then have a separate tank that runs a mixture that needs to be pre-heated.
I need to read up more to understand how exactly they work.
Sorry to OP who I think was trying to find out how to make up the mystery mixture.
One reference stated that dealers/sellers needed some sort of license to make/sell it. See below references:
https://www.fofh.co.uk/tech/tvo.htm
"TRACTOR VAPORISING OIL
There must only ever be 2 ingredients in TVO
- Petrol (unleaded is absolutely fine for a Ferguson tractor) 98 Octane
- 28 Second Heating Oil 20 Octane
Aim for an Octane value between 55 and 70
- 55 if doing very hard work
- 70 if doing topping and the like
To give you some idea of the sums:-
- 1 petrol and 1 heating oil comes out at 59 Octane
- 2 petrol and 1 heating oil comes out at 72 Octane
- 1 petrol and 2 heating oil comes out at 46 Octane
- Petrol on its own is suitable for road runs (with the heat shield removed).
Octane is not the only factor, but is provides a good guide line
Dieselfuel is designed to cause ignition by compression and will encouragepinking. It is not designed to burn in TVO tractors, and no uppercylinder lubricant is required in these tractors, so do not useanything other than petrol and heating oil.
Using fuel whichdoes not burn completely will destroy the lubricating properties of theoil and that (in a Ferguson TE tractor) will result in wear to the camshaft bushes and then loss of oil pressure from cam shaft bushes. Lossof oil pressure will, then result in damage to the crank shaft.Lubricating oil in a TVO tractor's engine should be changed accordingto the Tractor Instruction book."
https://www.fofh.co.uk/tech/tvolic.htm
"GET A FREE TVO LICENCE AND BE LEGAL
Anyone in the UK who purchases heating oil (Kerosene) or obtains it in any other way to mix with other oils to make Tractor Vaporising Oil (TVO) is now required to have a licence to do so. The selling dealer of Kerosene will require you to show your licence before he can sell to you.
Thre are a number of very strict restrictions that must be obeyed or HM Revenue & Customs will withdraw the privilege and any breach of the terms may consitute an offence.
The restrictions are:
- You cannot use rebated gas oil (red diesel) in the mixture under any circumstances, unless the tractor is only being used for bona fide agricultural, horticultural or forestry work. This of course excludes road runs, shows, ploughing matches or any domestic or pleasure activities.
- The concession only applies to tractor models that were in production before 1960.
- The mixed fuel must not be used in any other vehicle
- The fuel must not be mixed in bulk for resale or storage.
The FoFH has obtained a general licence, which we can issue free of charge to paid up members.
To obtain a copy of this licence send a stamped addressed envelope, your membership number, make & model of tractor, serial & engine numbers to:-
Bob Wood, 9 Crawley Cresent, Trowbridge, Wilts, BA14 9SW"