Just posted to YouTube is a run with no ether OR kerosene but with only Mineral Spirits as the fuel ingredient at 80% with the 20% being castor oil. No DII or cetane booster was used in any of these tests.

At first, an all kero, no boost mix was run to establish settings and to use as a bench mark. On this day, on this engine, the all kero fuel ran pretty well with good idle and transition. This may have been due to the new barrel with the reduced bore. I may make another barrel with an even smaller bore.

Using Mineral Sprits we found that the idle was good and the transition slow but reliable. It also took a little bit for the top end to settle down. Top end was some 500 RPM down from the kero run. Mineral spirits have a similar auto ignition temperature at 230C with kero at 210C so it's not any wonder that it works. A tighter compression was needed for a start and once warmed up, the final CR was a bit tighter than the kero fuel. The needle needed to be taken out a half turn.

Next run was the BBQ lighter fluid. The bottle says that it contains naphtha, hydrotreated heavily. The word contains implies that that is not the only ingredient. The run with this fuel was similar except the best idle I could get was higher by a few hundered RPM. The top end was equal to kerosene at 9.5K. Idle was good but transition was also slow. Full RPM also needed time to settle down. A bit more compression was needed and the needle out again a bit more.

And finally, I ran the Camp fuel. The can simply says, "contains naphtha petroleum". This mix was extremely difficult to get going. It took over half an hour to do that and the run was rough and way low on RPM at only 7K. The compression had to be maxed out a full 3/4 turn tighter. Also, the needle had to be backed off to the point where it was falling out. But the *&^% stuff ran. I can only surmise that there was a lot more naphtha in this mix compared to the BBQ fluid. And that figures, naphtha has an AIT in excess of 450C.

All of these runs were with no additives just to test the realative burnability of the various volatiles compared to kerosene. No reason except curiosity. The problem of course, is that it's hard to get exact information on the precise make up of certain- products on the market. Contains is the operative word. What else is "in there" may be the problem with finding alternate fuels.

So why bother, kerosene is cheap, available and works. Do we NEED ether? It appears not except as it affects throttling.
And, of course as a primer to allow a start on no ether.

Kerosene and cetane boosters will be tried with these other fuels and that might give us a clue at to where we go next.