It has been sold the etherless fuel and the engine was easy to start up without ether.
Those who knew etherless fuel recipe and sold into the market went into the grave without leaving a recipe on paper or to the heirs. [] See the pic..

There is no wrong to run the model diesel fuel etherless. It is up to each user to choose either the fuel containing ether or without ether. Not all countries in the world have users access to the ether because of strict laws about the abuse of the ether or not available to buyers. We give them a hope that there is the etherless fuel they can use in their model diesel engines.

Davis Diesel Fuel is not sold to other countries outside the U.S., same with the Model Technics diesel fuel is not always available in all countries in Europe. So we have to make own fuel and have access to the ether, in some countries in Europe are not all lucky to get ether because of the law.

I have spent time chasing after etherless fuel in old books in the internet and in book markets. And I found only three books containing the recipe for etherless fuel. The books were put away in the library's stock or filed as old books in the archive that scanned books that not everyone has access to the public library's shelves or sold on the used market.
That's because ether can disappear from the market due to those who produce drugs destroyed so much for us, both you and me who want to fly model airplanes with model diesel engine.