I did not check the spark plug boot but will, thanks Dave. Such low hours don't believe it has ever been off.
And thanks Rob for the blanket statement of supremacy. I'll try your method also.
One of the reasons I spray into the foam filter is to not overdose the engine.
When I see what folks do on youtube I can understand why you have a concern, but remember please
that many tractor builders had an ether dispenser built into the tractors for many years.
On inexpensive small engines with design specs not meant to handle the volatility of ether/starting fluid sure
you'll have problems, because that's the general public. I think most of us know not to overuse starting fluid.
I believe I read that WD40 can be used also. Perhaps a squirt container with fresh gas would be best.
I'm using 93 octane non ethanol in everything.
waiting for it to warm up so I can try again.
Obviously, many things that will work for testing carry huge flammability risk.
(Preaching to a fireman, I know

).
Done in open-air (non-confined space), that's one thing I like about the propane approach - it can get the engine to at least cough/run, but is less likely to create external flames. One other thing I've seen used for this type of testing is Brake Cleaner - with 2 caveats - not all formulations of brake-cleaner spray work well, and it's highly flammable. The one thing that brake cleaner spray has going for it is that it's designed to evaporate quickly, slightly mitigating the flammability risk.
ALL of these techniques are risky. Judicious use of applied external fuels is key - overuse of most may just choke the engine, and can create major firestorms.
One thing working against us on these small engines is the carbs are mostly side-mounted. For testing automotive carbs (top-mounted), you can often get away with pouring small amounts (out of a tiny glass bottle, not a gas can !) down into the carb, while somebody else cranks. Carbs can backfire flames, so keep the fuel-source (and your head !) well out of the way if you ever have to do this...... And, for this approach, I have the air filter removed, as I don't want it saturated with gasoline.
That move ^ carries risk, but IMO, less than externally vapourizing gasoline.... that's a bit too close to flame-thrower territory for me

.
Anybody even slightly uncomfortable with this type of testing shouldn't do it. If you do, I'd highly recommend doing it outside, on a large gravel or concrete area. Use at your own risk, I accept no responsibility if you burn a hole in your pavement, or burn your garage and/or house down.....
Not joking.... ask a fireman how many household fires start in the garage......
Rgds, D.