Optimax help

[Flygaff]

I have twin 135 HP Optis on my 25 CC Ranger. Last year I had water in the fuel that just screwed up everything. After a month trying to fix it myself I had the boat hauled to D&R Boats in Green Brook. I had them do the repair that included pumping out the tank, changing out the high and low pressure fuel pumps changing all the filters and the winterizing and storing the boat for the season. $3800.00 bill. When I tried to use the boat yesterday all the problems are still there even thou they claimed that it pass all Dyno tests. The engine start and idle fine. As soon as they get a load they buck and stall. I get to 1800 rpm and then dead. No warning lights or anything. Any suggestions would be appreciated .