How to flush my boat engine with out Starting the engine

[itskev90]

Good Morning all,
I have an emergency, we went out yesterday and our boat stalled in the water.
we had to tow it on shore but the boat cranks but would not start.

How do i flush the engine without starting? I have a Mercruiser 7.4 L V8 inboard sea water cooled engine

[shrew]

Moved from the "Forum Support | Suggestion Box | News" sub-forum to 'Engines'.

Were you underway when the engine stalled? I would do two things:

1) Pull spark plugs and see if water drains from cylinders

2) Check oil level and see if it is overfull.

If either too much oil or water drains from plugs, I would do an oil change, then run the engine for at least 15+ minutes after coming to temp. and repeat 5-7 times.

[speedysprocket]

Did it stall from water ingestion?... If it stalled from lack of fuel or no spark, then there shouldn't be water anywhere in the engine that it doesn't belong, so there's no crisis to flush the cooling system.

[shrew]

Originally Posted by speedysprocket

Did it stall from water ingestion?... If it stalled from lack of fuel or no spark, then there shouldn't be water anywhere in the engine that it doesn't belong, so there's no crisis to flush the cooling system.

Doesn't really matter. If it stalled while on plane there is a good chance there is water even if that isn't the source of the original stall. Which is why I asked.

[Kevlar7r]

He never said he was on plane when it stalled, just on the water.

Why do you feel so compelled to flush the engine?

[mmwjr]

Not clear what you want to flush; cooling system, oil, cylinders, ...

Since you say it cranks I am assuming no water in the cylinders.

Seems to me you need to determine if its a fuel or spark problem as to why its not running.

[itskev90]

Hey, the boat cranks fine, the coil has oil in it. but the coil takes a week to get where i am. i need to flush the cooling water system. i was in the sea.

[speedysprocket]

Originally Posted by itskev90

Hey, the boat cranks fine, the coil has oil in it. but the coil takes a week to get where i am. i need to flush the cooling water system. i was in the sea.

Ignition coils typically have oil in them. Did yours crack and that's how you found there's oil in it...?

[mmwjr]

Originally Posted by speedysprocket

Ignition coils typically have oil in them. Did yours crack and that's how you found there's oil in it...?

I am wondering how he knows it has oil in it as well.

Anyway it can still be bad even with oil in it.

[mmwjr]

Originally Posted by itskev90

Hey, the boat cranks fine, the coil has oil in it. but the coil takes a week to get where i am. i need to flush the cooling water system. i was in the sea.

IMO not flushing it is not a big deal as flushing still leaves behind salt residue. However hook up the muffs and hose and crank it over a few times, the water pumps will turn and push some fresh water through.