cylinders drain straight to foot?

[Lewis]

I just got a 2013 Mercury 8HP 4-stroke. I knew it had issues: it supposedly had been submerged and is seized. There is no sign of corrosion on any of the fasteners, and it looks very good under the cowl. Sure enough, it is seized and there is rust on the flywheel. The first thing I did was pour some Marvel Mystery Oil in the cylinders. But as fast as I poured it in, it flowed out through the drain at the foot. How can that happen? I had planned -- as a first step -- to fill the cylinders with oil and let it soak for a few days. But instead I have a straight passage from the spark plug holes to the foot.
This is my first 4-stroke, so maybe I'm just all confused as to its anatomy. But I was sure surprised to see the oil just pouring out!
Lewis

 

[GA_Boater]

An exhaust valve is open.

You need to take off the timing belt and rotate the camshaft until both valves on a cylinder are closed, then add the MMO to that cylinder. Let it soak a day or two, then do the same to the other cylinder.

Good luck.

 

[Lewis]

GA_Boater,
Thanks for the quick reply! That makes sense. In the near term, I'm just going to pull the seized powerhead and replace it. I will save the rescuing/rebuilding of this one for some time in the future when I'm running short of projects.
Lewis

 

[merc850]

What about the oil in the crankcase it's probably contaminated. I would tear it apart now and clean the parts so the crank/valves etc. don't rust.

 

[Lewis]

merc850,
A little more background. I bought the motor online, from a shop that took it in as a trade-in. The trade-in customer represented that it had been dunked and is now seized. The shop didn't want to mess with it, just posted it for sale. Because I had it shipped to me, the crankcase was drained, and I don't know the condition of the oil.
But you bring up a good point: what should I do with the powerhead to prepare it for long-term storage and to ensure that it doesn't get any worse?
Thanks,
Lewis

 

[merc850]

Just take it apart inspect the parts for rust, I use Mercury's Power Tune to displace water and clean off rust then use Anti-Corrosion spray to preserve it. Any motor I get I tear down to see what I'm dealing with.