First things first.....I have a 1992 E200STLENS which has an electronic fuel pump just outside the gas tank.It is controlled by a toggle switch.Before starting,I flip the switch,pump starts running,turn the key,motor is running.Never a problem starting.

Today I noticed that when I flipped the fuel pump toggle,I didnt hear the fuel pump turn on like usual.Thought that was weird but went on anyway.Boat started fine,idled fine,when I gassed it to get on plane,it seemed as nothing was wrong.After I got on plane and trimmed up to approx 4,000 rpm the motor sounded like it choked and just cut off.Swamped the back end of my boat with backwash,it just flat cut off.

Is it safe to assume its a fuel pump gone bad?If so,why did it not cut out when I hammered the gas to get on plane?Why did it take so long to cut out?Seems it just wouldnt start at all if the fuel pump,in fact,wasnt pulling fuel.....correct?

Its got me puzzled....anybody got ideas?

Purely a guess..........

Maybe the motor ran until all the gas in the lines was used up? I've noticed in the past that my motors will run for quite a while if the fuel supply is pulled.

I doubt it was just running on the gas left in the carbs.  Those gas thirsty loops will barely crank on what little gas is in the carbs.  Most likely the pump was pumping a small amount of fuel, just was not making pressure or much volume, (probably why you couldn't hear it running).   When you nailed the gas, the pump couldn't keep up then.  It takes approx 5.5 psi and about 30 gph minimum to feed that motor.    Personnaly, I would have installed a relay to turn the pump on and off with with the key switch.   I run the Carter 7 psi @ 75 gph on them and run them on a relay.

When you nailed the gas, the pump couldn't keep up then.

It didnt cut out when I tried the hole-shot,it cut out after I had been on plane for about 15 seconds and was trimming up.That is whats so weird.Starting,idle and hole-shot all good.  :-? <-------

Thanks for your reply,keep it coming.

I suppose the decrease-increase-decrease in fuel need by the engine could've caused a air-lock in the line if the pump wasnt' pumping up to snuff.

You can always T a guage into the output of the fuel pump and see what it's doing.  If it's not maintain at least 5 psi, it's not going to feed that motor.   One little problem comes into play when the pressure drops on those carbs.   If the air box is still on it, I think those carbs have .062" main jets feeding the motor, but only have .052" orfices in the needle seats to let gas into the bowls.  Needless to say, for a .052 inch hole to pass as much gas as a .062 inch hole, the gas feeding the smaller hole has to be pressurized.   Any guage that will let you read 5 - 7 psi easily will work, I use a 15 psi, doesn't have to be a special guage just because it's fuel, pressure is pressure.

You might also want to take some voltage readings to make sure your pump is getting plenty of power.  Could just be a bad connection or switch.

The pump I mentioned is about $75 and get you one of those kits to hook up driving lights for about $15 and it will give you everything you need to add a relay, just throw the switch that comes with it in your spare parts junk box.  Go too small trying to save a dollar and it will probably melt a piston due to leaning the motot out from lack of fuel.