If its anything like old mercs that ive done fill the filters with clean fuel ,crank it over ,re fill if necessary, crack open the last injector union , crank over , check filters refill if ness, and keep doing that it should start ,total pain i know but that works with an old 814 that the wife had as a horsebox.
Stupid point is there enough fuel to cover the draw tube in the tank?
Is there a hand pump on the filters if there is theres a o ring that usually knacks on it ?
Jamie