All that cranking may have hydro locked it? If so you need to get the water
If you can turn the crankshaft over a few revolutions by hand, it's not hydrolocked.
Hard to start issues are sometimes loss of prime, in other words air in the fuel
Once you ensure it's not hydrolocked, I'd start with a compression
check as low compression
especially in cold wx will make one hard to start.
Does this engine
have glow plugs? Inop glow plugs will definitely make one hard to start, but I don't think you have glow plugs.
If you do, never, ever use ether on an engine
that has glow plugs, unless you ensure you don't use the glow plugs.
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