Engine Overheated and now boat wont start, need help. Possible Causes?

Both aod
If you had water in your cylinders, It’s very likely you have water in the oil. (Bet on it). It isn’t obvious from the dipstick. It will be obvious from the first couple of drips from your remote drain. Was the water on both sides, or just one side of engine?
Both Sides
 
the sooner you get her started and heated up to dry out the moisture the better. That’s why they say 48 hours, your trying to beat the rust starting internally in your motor.

good luck!
Will have it started in a couple of hours... hopefully
 
Like I said in a earlier post, be ready to change the oil once if not twice! And change that pump! That one part in the root of all the work you are doing now!
Noted, I’m going to buy all the stuff for the oil change and bring it with me, thank you
 
Update #2: I compression tested all the cylinders today, they all tested good. I put new plugs in, changed the oil, you guys were right it was full of water. I am going to change it again tomorrow just to make sure all the water is out. I replaced the sea water pump. The bearings were completely shot on the last one, it was seized and mangled. Before I removed the serpentine belt, after i replaced the plugs the boat did start but not easily. As soon as I removed the belt and that seized pulley was no longer in the equation (I didnt at the time realize it was seized), the boat started right up. After finally getting everything back together I took the boat out for a spin, and it sounded and felt great. The temp was right around 170 and consistent, which is what it always ran at before the water pump issue. When I saw the water in the oil as bad as it was, I immediately called my mechanic thinking I was going to need to bring it in and there was catastrophic damage. He said since the compression test were good, that he didn't think I had anything wrong with the head gaskets. He said he has seen it before several times where a boat overheats and water comes in through the risers. Im hoping thats what happened, and I escaped any major damage. He told me to run it for a bit and if everything seemed fine, I am probably good, and if not to bring it in. The only issue I am experiencing now is that something is squealing on the serpentine belt. i am going to replace the belt tomorrow, since it had it pretty rough with the seized pulley and see if that fixes it. If not it is probably one of the bearings on one of the other pulleys, I will figure out what part is going bad and replace it. Thanks to all the help from everyone, you guys were all spot on and I learned quite a bit, very much appreciated.
 

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Please please check your plugs to make sure you aren’t getting any water after running for awhile. I know it is a pain, but important to be on top of things. Sometimes it isn’t apparent until letting it sit for a couple of hours after running, as the water in manifold will leak. It is possible you cooked your manifolds, and your engine may run fine by blowing those slow leaks through exhaust. Trust me, I know first hand.
 
Please please check your plugs to make sure you aren’t getting any water after running for awhile. I know it is a pain, but important to be on top of things. Sometimes it isn’t apparent until letting it sit for a couple of hours after running, as the water in manifold will leak. It is possible you cooked your manifolds, and your engine may run fine by blowing those slow leaks through exhaust. Trust me, I know first hand.

thank you, will do. The plugs weren’t too bad, they were honestly probably the quickest and easiest work I did today. I will run it tomorrow after work, and then check them on Thursday after work
 
Please please check your plugs to make sure you aren’t getting any water after running for awhile. I know it is a pain, but important to be on top of things. Sometimes it isn’t apparent until letting it sit for a couple of hours after running, as the water in manifold will leak. It is possible you cooked your manifolds, and your engine may run fine by blowing those slow leaks through exhaust. Trust me, I know first hand.

how much of a pain in the ass are the exhaust manifolds to change if there is an issue?
 
It’s not necessarily difficult, but really depends on how much real estate you have on sides of motors. Keep an eye and regularly check each of the plugs for awhile after running. Also, change oil 2 or 3 times and after each run, quickly check your oil through your remote drain after each use for awhile. Water will always come out first, so it doesn’t take much. How did you do a compression test? Leak down tests always are more telling, but they are notoriously difficult on those MPIs. (Hard to get exact position in cylinder).
 
Update #2: I compression tested all the cylinders today, they all tested good. I put new plugs in, changed the oil, you guys were right it was full of water. I am going to change it again tomorrow just to make sure all the water is out. I replaced the sea water pump. The bearings were completely shot on the last one, it was seized and mangled. Before I removed the serpentine belt, after i replaced the plugs the boat did start but not easily. As soon as I removed the belt and that seized pulley was no longer in the equation (I didnt at the time realize it was seized), the boat started right up. After finally getting everything back together I took the boat out for a spin, and it sounded and felt great. The temp was right around 170 and consistent, which is what it always ran at before the water pump issue. When I saw the water in the oil as bad as it was, I immediately called my mechanic thinking I was going to need to bring it in and there was catastrophic damage. He said since the compression test were good, that he didn't think I had anything wrong with the head gaskets. He said he has seen it before several times where a boat overheats and water comes in through the risers. Im hoping thats what happened, and I escaped any major damage. He told me to run it for a bit and if everything seemed fine, I am probably good, and if not to bring it in. The only issue I am experiencing now is that something is squealing on the serpentine belt. i am going to replace the belt tomorrow, since it had it pretty rough with the seized pulley and see if that fixes it. If not it is probably one of the bearings on one of the other pulleys, I will figure out what part is going bad and replace it. Thanks to all the help from everyone, you guys were all spot on and I learned quite a bit, very much appreciated.

Your 170° temp is a sign to me that some items still need to be attended to.

Open up the old pump and check to see if any impeller vanes are missing. Any missing pieces need to be found and removed, check the P/S cooler for them.

Can you keep your hands on top of the risers or are they too hot?

When was the thermostat last replaced?

You should be closer to 160° temp with the proper thermostat and everything thing else working properly.
 
Agree, 170 seems a bit high. Check the old impeller looking for missing rubber, mine alway seem to go to the trans cooler. Check those risers, and yes I would change that belt out.

Since finding and posting on CSR I've learned how to fix many issues with my old girl. Members are a wealth of information and I glad things worked out for you but your not completely out of the woods yet
 
It’s not necessarily difficult, but really depends on how much real estate you have on sides of motors. Keep an eye and regularly check each of the plugs for awhile after running. Also, change oil 2 or 3 times and after each run, quickly check your oil through your remote drain after each use for awhile. Water will always come out first, so it doesn’t take much. How did you do a compression test? Leak down tests always are more telling, but they are notoriously difficult on those MPIs. (Hard to get exact position in cylinder).
I did the compression test with a Cylinder Compression Tester Gauge
 
Your 170° temp is a sign to me that some items still need to be attended to.

Open up the old pump and check to see if any impeller vanes are missing. Any missing pieces need to be found and removed, check the P/S cooler for them.

Can you keep your hands on top of the risers or are they too hot?

When was the thermostat last replaced?

You should be closer to 160° temp with the proper thermostat and everything thing else working properly.
The Impeller and the O ring on the old pump were both in great condition, It looked like that part of the pump had been recently rebuilt, but the bearing was shot. I did not feel the risers. I do not know when the thermostat was last replaced, or if it has have been replaced. I have only had the boat a short period of time, and I have not replaced it.
 
Agree, 170 seems a bit high. Check the old impeller looking for missing rubber, mine alway seem to go to the trans cooler. Check those risers, and yes I would change that belt out.

Since finding and posting on CSR I've learned how to fix many issues with my old girl. Members are a wealth of information and I glad things worked out for you but your not completely out of the woods yet
Yes, this has been a tremendous help, everybody has been spot on with all their troubleshooting. Def changing the belt out, its been put through some abuse for sure.
 
Do you suspect this was a salt boat at some point? just trying to figure this water in the cylinders out.... which would go right along with manifolds in salt that corrode away...
It was never in Salt water, the duration of its life before me was lake Champlain in NY.
 
It was never in Salt water, the duration of its life before me was lake Champlain in NY.

its odd then.... my understanding is freshwater manifolds should last forever, i have had boats 30 years old, never an issue in fresh...

so something/somewhere caused this to backfill the cylinders.... i wouldnt think its because of a bad bearing on the water pump....
 

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