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

Chris-380 said:
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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I dont know that the manifolds are bad, that was just mentioned in this thread as something to check out. My mechanic thinks the water came in through the risers when the boat overheated, he said he has seen it happen several times before. It was overheating for 15-20 mins because it was in a channel when it happened and it was not a safe place to kill the engine. The manifolds may be perfectly fine
 
Chris, they have told me 8 to 10 years on my FWC risers and manifolds. I had mine done when I bought the boat, they did show some issues. Mostly with the gaskets. That's been 7 years ago.
 
dwna1a said:
Chris, they have told me 8 to 10 years on my FWC risers and manifolds. I had mine done when I bought the boat, they did show some issues. Mostly with the gaskets. That's been 7 years ago.
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Mine are 20 years old, I guess I need to pulled them at some point. Been boating for 35-40 years, never heard of issues here in the Midwest with risers/manifolds
 
I changed the oil again today, and put a new serpentine belt on. The squeal is gone. Temp is still around 170, I will check to see if there is any debris anywhere tomorrow, and if not replace the thermostat. I def want to take out the risers and check them out, and replace the gaskets or the whole part if they need it. Thankful the boat is running well again. Will take the plugs out again over the weekend and check for water, and will probably change the oil one more time next week. Do the whole risers usually need to be replaced usually? or just the gaskets?
 
Stagger said:
I changed the oil again today, and put a new serpentine belt on. The squeal is gone. Temp is still around 170, I will check to see if there is any debris anywhere tomorrow, and if not replace the thermostat. I def want to take out the risers and check them out, and replace the gaskets or the whole part if they need it. Thankful the boat is running well again. Will take the plugs out again over the weekend and check for water, and will probably change the oil one more time next week. Do the whole risers usually need to be replaced usually? or just the gaskets?
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I agree with what was said above about the bad pump not causing the water ingestion. Definitely change your thermostat. There is a reason why the water got in there, and it might be secondary from the overheating. If you are going to change out the riser and elbow gaskets, remove the manifolds as a manifold gasket is $14.00 and that gasket might be the point of failure. Put a cap on the bottom and pour acetone into the manifold (water side) on your driveway and see if the acetone leaks out the exhaust side of manifold. The riser (riser between manifold and elbow) and elbow are the stronger points especially on a fresh water boat especially if they have the separate water jackets (round). It’s also difficult to pressure test those. It is possible that while overheating you trashed your flappers, and that in rough seas you stopped very quickly or backed up at a high speed to allow water to flush backward. (This would be an extreme event and not likely, although it is technically possible). You can check your flappers without much disassembly and something you should do after an overheat. If you continue to get water in the cylinders, I would hope it would be coming in from the exhaust side. The other alternatives would be head gasket (out of experience, you can still have compression, better to do leak down test), or your intake or intake gasket bad. Wishing you all the best! Be careful and be vigilant at this important time to check for water.
 
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MExcelsior said:
I agree with what was said above about the bad pump not causing the water ingestion. Definitely change your thermostat. There is a reason why the water got in there, and it might be secondary from the overheating. If you are going to change out the riser and elbow gaskets, remove the manifolds as a manifold gasket is $14.00 and that gasket might be the point of failure. Put a cap on the bottom and pour acetone into the manifold (water side) on your driveway and see if the acetone leaks out the exhaust side of manifold. The riser (riser between manifold and elbow) and elbow are the stronger points especially on a fresh water boat especially if they have the separate water jackets (round). It’s also difficult to pressure test those. It is possible that while overheating you trashed your flappers, and that in rough seas you stopped very quickly or backed up at a high speed to allow water to flush backward. (This would be an extreme event and not likely, although it is technically possible). You can check your flappers without much disassembly and something you should do after an overheat. If you continue to get water in the cylinders, I would hope it would be coming in from the exhaust side. The other alternatives would be head gasket (out of experience, you can still have compression, better to do leak down test), or your intake or intake gasket bad. Wishing you all the best! Be careful and be vigilant at this important time to check for water.
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Thank you, i appreciate the process on how to test all those things, and I will do so. Great information!
 
Update #3: Ran the boat a couple of days ago (Wednesday) for a few hours and it seemed good. It sat for the last two days and today (Saturday) I pulled the plugs again, and they were bone dry! Im not sure if im out of the woods yet, but I feel much better about where i am at. Couldn't take it out today, as soon as I was done with the plugs it started to pour. Thank you everyone again for your help. I will probably change the oil one more time next week, and change out the thermostat to see if that makes any difference for the temp on the heat gauge. Last time i took it out it was still consistently showing about 170. Thank you again everyone for your help and information!
 
You know it could just be that the gauge is wrong. IR thermometer might give you a better reading.

Just a thought
 
dwna1a said:
You know it could just be that the gauge is wrong. IR thermometer might give you a better reading.

Just a thought
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Yea I had a couple people suggest I do that, and tell me that the gauges are notoriously inaccurate
 
Stagger said:
Yea I had a couple people suggest I do that, and tell me that the gauges are notoriously inaccurate
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My boat is a 2000, my guage will sho close to 175/180 and my fox gateways will be at 163/165.... and the difference between the 2 motors looks to be 10-15 degrees and shows 2-3 degrees on the gateways... so I agree, the dash gauges are not that accurate.
 
Stagger said:
Update #3: Ran the boat a couple of days ago (Wednesday) for a few hours and it seemed good. It sat for the last two days and today (Saturday) I pulled the plugs again, and they were bone dry! Im not sure if im out of the woods yet, but I feel much better about where i am at. Couldn't take it out today, as soon as I was done with the plugs it started to pour. Thank you everyone again for your help. I will probably change the oil one more time next week, and change out the thermostat to see if that makes any difference for the temp on the heat gauge. Last time i took it out it was still consistently showing about 170. Thank you again everyone for your help and information!
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I'm glad to hear that everything was dry. Please bump the engine over a couple of times before checking the plugs to make sure they didn't dry while sitting. I still trying to solve the mystery of how water got there in the first place. Was the impeller missing any vanes/blades when you removed the old pump. Could it be that you might have hooked up to muffs and a hose and somehow the pressurized water from your spigot got past missing vanes into the engine? (Normally pressurized water doesn't get past the pump impeller). Thanks, Mike
 
MExcelsior said:
I'm glad to hear that everything was dry. Please bump the engine over a couple of times before checking the plugs to make sure they didn't dry while sitting. I still trying to solve the mystery of how water got there in the first place. Was the impeller missing any vanes/blades when you removed the old pump. Could it be that you might have hooked up to muffs and a hose and somehow the pressurized water from your spigot got past missing vanes into the engine? (Normally pressurized water doesn't get past the pump impeller). Thanks, Mike
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I actually didnt turn the engine over before I pulled them, bc I didnt want the boat to start and the combustion to dry the water if there was any. I suppose I could pull the wires and then crank the engine a couple of times and then pull the plugs. Impeller was all there, it actually looked like someone had rebuilt it fairly recently, the O ring looked new also. Besides the bearing, the pump was in great condition. But that bearing was mangled. I dont know how water got in either, when I talked to my mechanic on the phone and described the problem, he said he has seen it before when an engine overheats for water to get sucked in from the risers. His exact words were actually "I dont know how it happens so dont ask, but ive seen it where an engine overheats and water comes in through the risers" I do not understand how that would happen, but i admittedly dont know very much about boat engines, and Im learning as I go. So far everything is sounding and feeling great. I am getting a squeal im assuming from the serpentine belt when I put the boat into gear, but its short and goes away immediately, thats my next issue to track down. Its a new serpentine belt so i may just need to adjust the tightness of it.
 
dwna1a said:
It does sound to me as if she is hydrolocked, especially after the comment about needing a new raw water pump. If you go down there today don't be fooled if the engine turns over.

Pull the plugs and get the water out. Get some Marvel Mystery Oil and inject it into each cylinder Then rotate the engine again. If you're good with motors great, you will save some boat bucks. If not get a mechanic and get the ball rolling. Let the mechanic know about the raw water pump and have him replace it. Also might be a good time to change out the risers and manifolds. Whatever you do, get the water out!

Also be prepared to be changing the oil at least once if not twice.

I'd be about 90% sure this all stems from the bad raw water pump. Once it failed the only thing moving water was the forward movement of the boat. When you slowed for the No Wake you were no longer cooling the engine. She overheated and the damage was done.

Let us know what you find and decide to do. Good Luck
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SOOO Sorry ! I know how you feel,Well you are in luck now thou, you get to make everything the right way w/all this help at your finger tips,DON"T go the cheap way rebuilding, GOOD LUCK
 
Thanks for all the great info..Glad the outcome was positive
 
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