Overheating issue

[MonkeyBiz]

Hello all,

I had an issue last weekend with my 2002 2900 SCR 6.2. Launched the boat and within 5 minutes, the temp was at around 175 degrees. Had the same issue last spring and it slowly returned to normal operating temp so just figured there was air in the system so I let it idle probably a little too long this time. It did not cool down so I shut her down and let it cool for a while. There was water dripping into the bilge at the rear, I think in the area of the exhaust Y and I could hear water gurgling internally. When I tried to restart, the engine was hydro locked. I removed the plugs and water came out of #5 only. Took the boat to a local marina and they checked for cracked block or any other catastrophic damage and they assured me that there is none however, they are backed up with work and will not be able to go any further until after Memorial day. I would like to get the boat back in my hands and start digging into it myself. My first step is to remove and replace the impeller and from there, does anyone have other thoughts/suggestions? Any advice would be greatly appreciated!

[mmwjr]

First perform a compression test of the cylinder to see if the head gasket is blown. How does the engine oil look and signs of water in it?

Next time you run the engine use an IR temp sensor to get real readings of the engine and exhaust.

Do you boat in salt water? if so has the exhaust ever been inspected or replaced?.

[MonkeyBiz]

Originally Posted by mmwjr

First perform a compression test of the cylinder to see if the head gasket is blown. How does the engine oil look and signs of water in it?

Next time you run the engine use an IR temp sensor to get real readings of the engine and exhaust.

Do you boat in salt water? if so has the exhaust ever been inspected or replaced?.

Oil looked fine but plan to change anyway. Boat is in fresh water and has been it's entire life but probably wouldn't hurt to check the risers and manifolds.

[jrsick]

I recommend you remove all of the plugs and motor the starter to check for water in the cylinder.
Checking risers and manifolds is good start.
When you change the oil, do you pump it out or drain it through the hose? The hose would be good for this oil change because any water should come out the hose first since it is the low point of the oil pan.

[shrew]

Check to make sure the intake hose hasn't slipped off. I had that happen on a Mercruiser 8.1. There was a recall a number of years ago. The 'manifold' (?) the intake was connected to was plastice and would sometimes crack when overtightened, causing leaking and overheating. This was replaced with a metal part.