Water in 4 cylinders

My 350 mag with 230 hours on it had water in 4 cylinders. And the way I found that out was it didn't want to turn over. It cranked and locked up. Pulled the plugs, got the water out and ran the motor. The risers and manifolds are 5 years old. I pulled the risers today and other than surface rust I couldn't see anything wrong with them. I put it back together and ran the boat. It ran very smooth until it bogged down for a second, it did that 4 times and then ran fine. I got back to the dock and opened the engine compartment. There was oil all over the starboard side of the engine. It came out of the dip stick. I checked the dip stick and it was secured properly. I pulled the dip stick and there was evidence of water in the oil.
So my question is, could bad risers cause water to get into all 4 cylinders on that side.
Or is it a head gasket or worse a blown motor?
Below is a picture of the inside of the riser.

Thanks for any responses.

That’s more than surface rust. You in salt? If so you’re over due for new risers.

Fresh or raw water cooled??

dan313 said:

My 350 mag with 230 hours on it had water in 4 cylinders. And the way I found that out was it didn't want to turn over. It cranked and locked up. Pulled the plugs, got the water out and ran the motor. The risers and manifolds are 5 years old. I pulled the risers today and other than surface rust I couldn't see anything wrong with them. I put it back together and ran the boat. It ran very smooth until it bogged down for a second, it did that 4 times and then ran fine. I got back to the dock and opened the engine compartment. There was oil all over the starboard side of the engine. It came out of the dip stick. I checked the dip stick and it was secured properly. I pulled the dip stick and there was evidence of water in the oil.
So my question is, could bad risers cause water to get into all 4 cylinders on that side.
Or is it a head gasket or worse a blown motor?
Below is a picture of the inside of the riser.

Thanks for any responses.View attachment 87202

Click to expand...

How bad are the elbows. If the water jacket is compromised it could be dumping back into the manifolds.

I would pump out all the oil/water asap to prevent any internal damage from rust. And fill with fresh clean oil.

Let me know if you need any help or angood pump.

-Kevin

I changed the oil today. And found no water in it. I took the boat for a ride and when I got back to the dock I checked it again. No water. The motor ran smooth and strong. Wherever that water came from is a mystery. When I pulled the risers the 4 bolts that hold it all together were hand tight. The mechanic who did the job 5 years ago never torqued them down. Your guess is as good as mine.

Had water getting into starboard cylinders on a 5.7 MCM 210 Sea Ray causing it to hydro-lock and found that the exhaust Y pipe water shutter flappers where deteriorated to point where one flapper was completely gone and other heat deformed so bad it wasn't stopping any backflow. Replaced both sides and haven't had that problem since.

I was also thinking the flappers were bad. I'll have to take a look when I get a chance.

Thanks,