G'day all,
A few threads about McDonald Diesels on the TOMM forums;
https://forums.tomm.com.au/index.php?topic=4689.0

https://forums.tomm.com.au/index.php?topic=1632.0

https://forums.tomm.com.au/index.php/topic=2435.0

From these, I'd say that it's apparent that ether-based starting spray/fluid [e.g. Aerostart, Start Ya Bastard] is a bad idea in these engines.
Using kerosene for starting is the go [after all, that's why it has a two-compartment fuel tank], and the hot water in the cooling hopper trick would be worth trying.

The other issue raised there, is that the Brons/Hvid fuel vapouriser can be rather temperamental to set up. Also, the fuel valve is prone to leaking, especially as the spring weakens with age.

A detailed rundown on the setup: http://www.oldengine.org/members/kennedy/mcdonald/vapouriser.htm

Cheers,
Gadge

"ODK Mods can explain it to you, but they can't understand it for you..."

"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."