Yamaha 250hp HPDI Engine sputtering

[al_southshore]

Hi folks, Im new here, as I just found this forum. I went fishing today for Mackeral, and noticed my engine seemed to be having a fuel delivery problem. It stalled several times, but restarted after I squeezed the primer bulb forcing fuel to fill the on engine filter and lines. The exhaust showed no signs of water (steam) which was what I first thought the problem was. I had read many articles about pros/cons of storing gas tank empty vs full; re: condensate and ethanol issues. Ive been maticulious about new filters and plugs, etc. Before storing for winter, I added Startron Fuel stabilizer to about 50 gallons. I ran 1/2 throught the system before hauling the boat last fall. I added another 150 gallons of fresh fuel from a street service station, prior to launching the boat last week, and added a large bottle of Stabil. I examined the on engine fuel filter canister and the gasoline has no signs of contamination. When I swapped out the remote fuel filter prior to launching the water compartment was bone dry, and the fuel showed no sign of contamination. The boat ran fine at low RPMs, say 2000, but when I approached 3700-3800 RPM the sputtering became more pronounced and audible. I couldnt tell if it was exacerbated by getting up on plane, or it was actually the RPMs, as those two things occured at the same time. I'm now thinking its the fuel pump. Any feedback would be greatly appreciated. Thanks, Al.

[99yam40]

You have multiple fuel filters, screens, and low & high pressure pumps on that motor. Test fuel pressures at the different points, change filters, and screens. If the high pressure rail does not have low pressure at problem PRM then you still may need to pull the injectors and send of for servicing.
Running cylinders lean will eat pistons.

[al_southshore]

Thanks

Thanks for the information. That may be beyond my field of expertise, and unless the problem is obvious, I might opt for having a Yamaha Rep look at it.