2005 Captiva R1 with 5.0 Mercruiser and Alpha 1

Txtechfan98

4th of July trip to the river for some watersports and just out of the no wake zone went to throttle up and boat started to get on plane, then a beeping alarm and bogging down, hesitation.  No evidence of overheat, checked for something wrapped around prop or outdrive, and nothing.  Boat would start up and idle (no alarm), but each time attempted to throttle and get on plane alarm beep would come on.  Got back to trailer, pulled it out, and headed for the boat shop to see if they could help me figure it out.  Spoke with mechanic at shop and he asked if we had bad gas/ had filled with something recently- most of the jobs as of late have been old fuel related- (it shouldn't be with mine as i put 30 or so gallons in two weeks ago).  bought a new fuel filter separator and replaced, pulled old one out and poured out contents and mechanic thought fuel was bad.  Started the boat out of water for a second in neutral and throttled up just to see if i could get the warning alarm to come on- (would not usually do this but the shop was almost an hour away and closed for next 3 days.)  didn't come on.  on way home stopped and put 11 gallons of premium fuel in just in case there was bad gas in tank.  When got back  went to ramp and boat is completely dead.  Blower works, accessories will  work, but won't even get a click or gauges to budge when turning key to on.  Looked for second fuel filter near cool fuel device at bottom of port side of engine- but i can't find it anywhere.  Any insight?  I can't figure out why i can't get it to start.  Two batteries with a switch between them and they both show to have full charges.  Boat worked fine two weeks ago.  Jumpwired the started solenoid and can get the engine to turn over but start- and nothing happens from turn of the key.