I'm lost with this one. I have good spark on all 4 cylinders, 118-120 psi on all cylinders just rebuilt the carbs two days ago thinking it could be a clogged jet. The motor idles fine but if I pull the two bottom plugs nothing changes still idles great. When I pull the two bottom plugs they are a little wet so they are getting fuel. Changed all plugs still nothing. I thought it could be the fuel pump but pumping the bulb doesn't change anything. I've pulled the fuel pump off to check to see if the diaphragm had a hole in it causing too much fuel into the bottom cylinders fouling the plugs. With the pump off I squeeze the bulb no gas is coming out so I'm assuming diaphragm has no hole. Gas is good I just drained it and put ethanol free gas in it. The boat has a built in tank and I unhooked the vent and blew air through it to make sure it was venting properly and it is. It does good up to about 3000 rpm then bogs down. I feel like it's something simple I'm overlooking. Any help is greatly appreciated.
