Ran Boat Without Cooling System

[freeheel4life]

Those plugs are expansion plugs that get pushed out by frozen water. When they do their job it keeps cast metals from cracking . Was most likely water leftover. I have never seen one pop out during an overheat anyways, but anything is possible...

[supervol0509]

Any idea if you can replace them, or if you have to replace the whole exhaust manifold? If it was to prevent cracking from freezing, I imagine just the plugs can be replaced.

[freeheel4life]

Any idea if you can replace them, or if you have to replace the whole exhaust manifold? If it was to prevent cracking from freezing, I imagine just the plugs can be replaced.

Yes they can be replaced, but it's not necessarily 100% guaranteed that there's not cracks internally that you cant see. I couldn't open your attachment either but if it's your exhaust manifolds and they are cracked internally water will leak into exhaust side. Easiest thing to do is plug it and run it on fake a lake and see. Measure hole diameter with ID calipers. Procure said size expansion plug/freeze plug and install it. They make some rubber ones that you tighten to fit. Lots of times they won't work for you as they are deeper and hit inner casting. Sized to fit plugs (brass I think) that will be "pressed" in are the ones you want. Usually a socket and a small deadblow to get them in. Prepping surface with some emery cloth first.

If you do suspect internally cracked and want to go nuts I remove them from the boat and do pressure test them.

[supervol0509]

So, I just got a rubber expansion/freeze plug from the auto parts store. I'm going to order some brass ones to replace the rubber one. Started the boat with the fake a lake, and engine ran normal, water fully flowed through cooling system, and engine temp was maintained.

The plug I replaced was from the exhaust manifold. Did not see any external cracks, but will recheck. While on in neutral, there is varying water flow through the exhaust discharge. It is minimal water flow for a several seconds, followed by about half a gallon fairly suddenly. I imagine this has something to do with water pressure building up behind the impeller, but not completely sure. I feel like I have noticed this before, but just disregarded since engine stayed cool.

So, what now? I would think there are enough engine safeties that we would not severely overheat the engine while on in neutral, but am not sure. We turned the boat off when we received engine alerts, yesterday, and never got it off the trailer. I've read about some people changing the oil after an overheating event, to see if there is water mixed in with the oil. Obviously, preference is to get back on the water ASAP, but just want to be thorough, after this event.

Are allengine temp sensors in the cooling system? I would hope there are other sensors that would indicate high engine temp before damage would occurs in an instance like this.

[freeheel4life]

So, I just got a rubber expansion/freeze plug from the auto parts store. I'm going to order some brass ones to replace the rubber one. Started the boat with the fake a lake, and engine ran normal, water fully flowed through cooling system, and engine temp was maintained.

The plug I replaced was from the exhaust manifold. Did not see any external cracks, but will recheck. While on in neutral, there is varying water flow through the exhaust discharge. It is minimal water flow for a several seconds, followed by about half a gallon fairly suddenly. I imagine this has something to do with water pressure building up behind the impeller, but not completely sure. I feel like I have noticed this before, but just disregarded since engine stayed cool.

So, what now? I would think there are enough engine safeties that we would not severely overheat the engine while on in neutral, but am not sure. We turned the boat off when we received engine alerts, yesterday, and never got it off the trailer. I've read about some people changing the oil after an overheating event, to see if there is water mixed in with the oil. Obviously, preference is to get back on the water ASAP, but just want to be thorough, after this event.

Are allengine temp sensors in the cooling system? I would hope there are other sensors that would indicate high engine temp before damage would occurs in an instance like this.

About the only other place you could put a temp sensor in your configuration would be in engine oil but it would read much higher than "coolant" or in your case water.
If you shut the boat down as soon as alarm went you are probably fine. I believe PCM has a lvl1 overheat and a level 2 overheat. First alarm at 1 is a general warning and lights lamp and buzzer at dash, at lvl2 overheat throttle is limited and basically forces idle.
If there is an internal crack it will most likely drop water into exhaust while boat is sitting unused, and when you go to run it it will throw codes shortly after you get off the trailer on your next trip out. If not cracked internally it will be back to normal boating.
Obviously keep on eye on your fluids and make sure they aren't mixing with water, which would indicate cracks elsewhere

[supervol0509]

We did have a couple of different audible engine alerts. As I said, we made multiple attempts at running the engine to see if it would work itself out. I don't recall an engine temp ever greater than 190, but not sure how accurate that may be, since there was no water flowing. I think I will slap in a new impeller and the r commended freeze plug, and just give it a go. If there are other issues from this event, hopefully, they'll present themselves, in some way, before further damage is done. I'll update the thread after next weekends adventure. Thanks for your responses.

[freeheel4life]

Keep an eye on engine oil and trans fluids. If either start getting milky then you know you have other issues.

[supervol0509]

Will do. Thanks!

[maxpow]

look around your mufflers when its running as well to make sure the high temp didn't cause a crack.

[supervol0509]

look around your mufflers when its running as well to make sure the high temp didn't cause a crack.

I checked the internal of the muffler from the rear of the boat before running it, and didn't see anything. I'll check it closely again, before heading out.

[supervol0509]

Just an update. Got boat out last weekend. Ran well. Fluids looked good, and oil pressure was good. Will keep an eye on fluids, but it looks like disaster was averted.

[supervol0509]

Update to this story. I went to fog my engine today, and found the spark plugs had some fouling. It was dry fouling, not wet, but now concerned, again, about this overheating incident in the spring. All the plugs were replaced, but now wondering if I need to have a compression test done.

On the freeze plug... lucky those are there. When I drained everything this year, there were a couple of plugs that I don't remember pulling last year, and, yes, they were in the exhaust system. All fluids looked good, when I changed them. Nothing milky, and oil pressure was fine all year. Been using one of the rubber freeze plugs in place of the removed one. Tried to get a brass one in there today, but of course dropped it, and could not relocate it. Not much space to get any kind of whack on the thing to get it back in there.