Volvopenta D6370KA no hot restart without priming

2009 d6370 straight 6 turbo in 29 ft hunt yatch,will crank hot but will not restart hot without manual priming fuel filter,checked history and history of running fuel dry,quit while running and very hard restart,tested fuel tanks for water,ok and for obvious leaks?no diagnostic codes present,any ideas thanks -roger

Check fuel filters and suction line for blockage. Also check return line for restrictions.

Air in fuel (especially if you have Racor filter(s)), vapor lock (fuel tank vent not working).

Try running the engine using portable fuel canister, for both pickup fuel line and return fuel line. See if problem persists.

Report back

Did you sort this problem? There is a new part available for the fuel return line to prevent similar problems to this on hot engines - in the case specified, it is to prevent engines stopping after restart, but I guess this could be related (on a hot engine, the fuel in the pump expands due to the heat from the engine, and replaces the fuel in the pump with air, hence the engine stops soon after starting, or in your case, will not start without priming)

You need to fit part number 21822234 to the return feed on the high pressure fuel pump - this contains a check valve that prevents the fuel escaping. I'm not saying this is definately the solution but worth a try if you cannot find any other problems and starting when cold is no problem?

Andy