3.0 omc bog at wot then dies.very hard to crank after

Idled for 10 min out of the boat ramp, went to wot for 2-3 min the boat bogged and died. It was very hard to crank (new battery). waited 5 min the engine cranked slowly but refired, i ramped up to wot bogged and died again. wouldnt crank. pulled plugs water in all 4 cylinders, im guessing from the immedate bog and die at wot?? water bakcwashing into manifold? Im leaning toward fuel starvation but any ideas?? strainer in carb spotless, filer in sediment bowl no real debis, new tune up, new fresh gas full tank, no ethonol. since ive had it (a year) it always seemed to bog a little on quick acceleration under load, i felt it was normal and avoided "gouging" on it. it ran great all summer.....help

Re: 3.0 omc bog at wot then dies.very hard to crank after

If it quit at wot the engine could have hydrolocked or you could have had water in the oil from the get go & didn't know it. Change the oil & filter post haste. What year is it? What it winterized properly?

Re: 3.0 omc bog at wot then dies.very hard to crank after

crouse67 said:

water in all 4 cylinders,

Click to expand...

that says exhaust manifold or riser failure (or the gasket at the joint between manifold and riser)

Re: 3.0 omc bog at wot then dies.very hard to crank after

Its an 86. The oil still looks great, it was changed the day before i had the trouble. It was winterized well. diconeccted all hoeses drained manifold and block refilled with rv antifreeze, fogged gear oil changed. Any thoughts on a fuel problem im into the tank now and the anti siphon valve seemed stuck (no air blown in or would suck out) i drained the tank and couldnt get any air to pass (50psi) im thinking the engine starved for fuel and the bogged at wot causing water to rush backwards?? how common is that?