I am usually good about slowing the boat gradually after making a run with a WOT. Not only to avoid bringing a large wake with me thats going to roll through the area I intend to fish, but also to avoid water pouring over the transom and into the back of my boat. On occasion though, there are times where we have all backed it off to quickly, and the wake comes up behind you and rushes the back of the boat. With the exhaust outlet being below the pee hole on the back of my 50 Merc, I feel there could come a time where the water can come rushing forward and pour right into the exhaust. I assume this could cause serious issues if this does in fact occur?

You would have to submerge or force water up the exhaust for this to be an issue. Also I assume your not cutting the motor off while running and letting it come to an abrupt stop so exhaust is being forced out the whole time and won't let any water in even if submerged

28 minutes ago, riverbasser said:

You would have to submerge or force water up the exhaust for this to be an issue. Also I assume your not cutting the motor off while running and letting it come to an abrupt stop so exhaust is being forced out the whole time and won't let any water in even if submerged

Yes motor is alway running. I don't shut the motor off until the boat has come to a rest in the water. 

14 minutes ago, NY_Jig said:

Yes motor is alway running. I don't shut the motor off until the boat has come to a rest in the water. 

You have nothing to worry about

Awesome, good to know!

You do realize the majority of the exhaust is underwater exiting through the prop hub, the upper port is a bye pass for the exhaust horns inside the hollow upper lower unit housing during idle, no direct connection to the powerhead cylinders.

Tom

On 5/17/2018 at 1:09 AM, WRB said:

You do realize the majority of the exhaust is underwater exiting through the prop hub, the upper port is a bye pass for the exhaust horns inside the hollow upper lower unit housing during idle, no direct connection to the powerhead cylinders.

Tom

I know now, thanks Tom!

The prop hub, not only an exhaust exit, but also a great place for mud divers to build a nest.  Few years back my buddy took his boat out after letting it sit under his carport for a couple months.  Engine started, but you couldn't throttle up, it would just bog down.  He figured it was a fuel issue, he tried all sorts of stuff and couldn't get it running right.  He brought it to the mechanic and they had trouble figuring it out, then one of the mechanics noticed some nasty brown sludge near the prop hub.  Turns out the mud divers nest had clogged up 90% of the exhaust port.  

17 minutes ago, Troy1985s said:

The prop hub, not only an exhaust exit, but also a great place for mud divers to build a nest.

Do you mean "mud dauber" as in wasps?

1 hour ago, J Francho said:

Do you mean "mud dauber" as in wasps?

Yeah.  I've always heard to him referred to as "mud divers" where I live.  One of several  different types of wasps waiting to lay into you while you're trying to do yard work in the summer.