I have my boat at the shop right now but man do they take forever this time of year.  I'm just checking to see if anyone may have a decent idea of what's going on.  Maybe I can even fix it myself.

 

When I get up on plane and am at 5000-6000rpm I will cruise along normally for some amount of time and all of a sudden something happens and the rpms go down drastically causing what I can only describe as a lunge.  The boat starts lunging forward.  I'll back off the throttle, pump the fuel ball (which is loose at this point) and continue on my way until it does it again.  It was sometimes a few trips between when it was doing that but I took it in because it was happening every 30 seconds or so.

 

My thought process is that it's something related to the fuel pump/fuel pressure.  What do you guys think?  

 

I'm not very mechanical or great at describing this so please let me know if more detail would help.  I just want to fish!

Primer Bulb or Fuel Pump. I would have put a new Primer Bulb on it and tried that before I left it some where.

Probably an air leak somewhere between the fuel pickup in the tank and the carb to motor block gaskets. Replace every bit of fuel line, rebuild the fuel pump, replace the fuel filter. If that doesn't work rebuild the carbs.

Thanks for the advice guys.  Getting a new fuel pump put on now.

Does this boat have built in fuel tank.  If so, make sure the vent is open.  I have seen them get a sag in the vent line that traps fuel.  This works like a P-trap in a sink drain can keep the tank from getting air.  Another problem I've seen a number of times is the anti siphon valve in the tank sticks and won't let fuel go through.  This valve is usually a check ball built into the fuel line barb fitting that's screwed into the tank.  To check it, just replace it with a standard barb fitting. 

If you happen to be using portable tanks, make sure you opened the vent on them.

From there you should make sure the fuel lines are passing fuel freely. 

Replacing fuel pump may take care of your problem, what you describe is a classic problem caused by a bad fuel pump. 

I would not consider the carbs suspect since you can pump the bulb and make it run fine.  This makes is sound more like a fuel delivery problem that's not getting fuel to the carbs.

An ignition problem can make one surge from cutting in and out but pump the primer bulb usually doesn't make that problem go away.