[Formula260SS]

Originally Posted by Dave R

I do not think your problem is electrical. I suspect your engine is hydro-locking with cooling water that is filling one or more cylinders through open exhaust valves. When you try to start it, the engine turns over until the water filled cylinder is on a compression stroke. As the piston in the flooded cylinder approaches TDC, the incompressible water stops it cold, and that puts an immediate halt on the starting process. When you keep trying to start it, the normal lack of a perfect seal in the valves and cylinder allows enough leakdown of the water to eventually let the engine spin over. Once it starts, the water clears very rapidly and the engine runs normally.

The two most common causes of marine engine hydro-locking are rapid deceleration combined with failed or missing exhaust shutters which allows water to rush up the exhaust sytem and pool in the exhaust side of the manifolds, or failed parts in the upper sections of the exhaust system that also allows water to pool in the exhaust side of the manifolds. Those parts include: manifold, elbow, riser (if equipped), or a gasket in between any of the listed parts. When you shut the engine off the pooled water goes right into any cylider with an open exhaust valve. If the engine happens to stop with the affected cylinder's exhaust valve closed, the problem does not occur.

You need to address this immediately. If the hydro-locked cylinder ever stops the engine after another cylinder has fired, the sudden stop can bend a connecting rod. Also, the water in there is certainly not doing your engine any good...

That's exactly what I thought, I had a boat years ago that had a cracked exhaust manifold and had the same problem.