[dkwalls]

Engine overheated need help. 2001 222 MAG 350 MPI. Left marina got outside of break water going 25 mph and temp alarm went off. Temp at 240. Immediately shut off engine and was towed back to dock ramp. Boat was towed from front bow. Took out the impeller and it was in pieces. Bought new replacement kit, tried starting and wouldn’t start. The belt turns ½ way and clicking noise. Took boat to mechanic and he said there is water in the cylinder walls and that’s why it would not start. He said all parts look fine and doesn’t show signs of overheating. He said somehow water got up in the exhaust almost like we were being towed backwards. We are trying a suggestion with the spark plugs will update findings in a bit. Does anyone know how can you tell if the manifold is cracked?

[SEMIJim]

The overheating may have melted the shutters in your exhaust system, which are what keeps the water out when the engine's not running. I'm surprised the mechanic didn't suggest this.

Jim

[dkwalls]

Update: pulled spark plugs, turned over engine 3-4 times did this 7 times this got out the water in the cylinders. Put spark plugs back in started engine right up. engine sounds and runs smooths, water tempature perfect. the only concern I have is: it was connected to ear muffs and we saw a few small pieces of black almost tar looking, texture, greasy feel to it. any clues on what the little particals could be?

thanks for your reply... I think we will try the exhaust shutters? do you happen to know where there located?

[SEMIJim]

Originally Posted by dkwalls

Update: pulled spark plugs, turned over engine 3-4 times did this 7 times this got out the water in the cylinders. Put spark plugs back in started engine right up. engine sounds and runs smooths, water tempature perfect.

You're going to want to change the oil two or three times to make sure you get all the water out of the lubrication system.

Originally Posted by dkwalls

the only concern I have is: it was connected to ear muffs and we saw a few small pieces of black almost tar looking, texture, greasy feel to it. any clues on what the little particals could be?

Yeah: Pieces of your old impeller and/or your destroyed exhaust shutters.

Originally Posted by dkwalls

thanks for your reply...

You're quite welcome.

Originally Posted by dkwalls

I think we will try the exhaust shutters?

I believe it'd be a mistake not to. I certainly would.

Originally Posted by dkwalls

do you happen to know where there located?

That I do not. Search (Google or whatever) on "Mercruiser exhaust shutters." Or maybe somebody else here knows.

Jim

[WetWilly]

Originally Posted by dkwalls

do you happen to know where there located?

Hi dkwalls, the exhaust shutters are located at the top of the "Y" pipe coming from the transome. Remove the rubber coupler hoses from the exhaust elbows to the "Y" pipe and you'll see the shutters.



WetWilly

[dkwalls]

thanks for the diagram. heading out to parts store now.... will update later on today.

[dkwalls]

changed oil 3x. took boat out on lake and runs perfect. Recommendations for overheating. 1 change impeller, 2 change spark plugs, 3 change exhaust shutters and 4. change engine oil 3x. this should all be done with in the first 24 hours. thanks everyone for your input.

[WetWilly]

Hey dkwalls, great to here you're back on the water and everything runs as it should!

WetWilly