I have a 30 HP long tail that is not running right. Took it out and I could not keep the fuel in the fuel filter, the ball kept going soft so I had to keep pumping it to keep pressure. It would only do this in thick weeds, the motor ran fine in open water. Got home and replaced all the fuel lines running from the tank and the filter. Put new plugs in also. The motor still runs like crap when running threw weeds, sounds like its flooding almost. It only does this when the motor is working hard, runs great in the garage. Any ideas on what to try next???

Crazy question but is the vent open?

Yes, tried vent open, vent shut, everything I could think of

Chec the pick up it the tank. If the bulb is going soft it a prob down stream of that.

Dose it have a fuel pump

I'm not sure if it has a fuel pump or not, its a 30 HP generac motor.
I checked the spark plugs out today after trying to start the motor for a good 2 hours. They are dirty and smell like gas, so I'm getting fuel to the plug. It also just started backfiring bad.

This is what the new plugs look like after motor ran for a hour or so. Starting to think its the carb that is not delivering enough fule

Like tin man said that is all that is left. Carb or pump

Have you try cleaning the carb, have you done any mods to the motor

Sound like the fuel pump diaphragm is dried up or has holes in it.

the motor has now been in the shop for 3 weeks. before I took it in we installed a electric fuel pump, and that did not fix the issue. The shop put a carb kit in it, new diaphragm fuel pump and still wont run. they ordered a new carb and as of now doesn't seem to be helping.

Replace the fuel tank...

Typically if the bulb collapses while the engine runs-that's either a pick up tube obstruction or a vent problem. If it gets soft while the engine runs its either a fuel pump problem or am air leak-meaning it's sucking air into the fuel line due to a crack or loose fitting or a hole.

May be a stupid question but did you replace the ball?