Anyway there is no way one fuel will work in all cases. A large engine would likely run just fine without ether in the fuel. But a little engine would need large amounts to run.
Engines in between have varying levels of need for ether.

I think having some way to pre-heat the etherless fuel would help a lot in how the engine runs. it is similar to how the large ocean going ships use bunker oil to run their engines. Hot fuel is closer to its self ignition temperature point and needs less pressure to get it to fire off besides being heated up thins it out more and it also tends to vaporize a lot easier too. Heating up the engine as well is good too.