Re: Yanmar 2gm2f no start after fueling
If you have an all-suction fuel pickup system leaks are very hard to detect.. fuel won't likely leak out, but air will readily leak in.
The squeeze bulb idea (like an outboard motor's priming bulb) can work, but in our case I suspect it was an air leak source. We've since gone to a Racor with a built in primer pump.
It does sound like you may have a serious (new) large air leak somewhere, or you've simply been unable to fully, properly bleed your system. All gaskets/seals/orings in place on your new filters?
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"