496ho no run

I have a 2005 496ho mag, yesterday we comm it at the marina started it up at the ramp ran great all temps and pressures,sounded great,left the ramp drove around the gas docks turned into the slips motor quit and would not restart, got into the slip tried to start would not turn over, tried to turn over with a breaker bar on the crank no go, left set tried again turned over very very slow batteries are ok herd a sound coming from port side manifold sounded like air puffing , last year there was a miss on that side put new wires and plugs talked to larry at raylar he said it possibley be a ring land, but my question is why did it start and run and made no noises just quit, any help woud be appreciated, thanks

tried to turn over with a breaker bar on the crank no go

Worst idea ever
,guessing its hydrolocked. pull all the plugs and then crank. see if water exits the cylinder

I would pull the spark plugs and check for water in the cylinders.

I would bring a magnet and see if it sticks to the exhaust manifold. If it sticks the manifolds are Iron. If not they are aluminum and the possible cause if water is found in the cylinders.


I would also take care of this problem right away. 496 long blocks are $$$$$$

If there's water in there (most likely) find where it came from before trying to run it. The usual culprit is a leaking riser gasket.

Note which cylinders have water--that'll show you where to look for the leak.

Get it fixed and running ASAP or the walls will start rusting.

Jeff