WHAT
- Thread starter sawdust
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Is the engine running hot at all? What kind of water flow do you have out of the exhaust? Could also be as simple as a water pump impeller not providing enough cooling (but not completely failed yet either), check the maniflds and risers, they should not be too hot to lay your hand on. A little steam in cooler weather is normal.
Steam can also more commonly be due to low RW cooling flow, either from damaged RW pump impeller or flow restriction such as clogged riser/elbow .
Feel the Riser/elbows -are they quite hot so you cannot keep your palm on them indefinitely?
Is the exhaust noticeably louder than usual (not quieted by proper RW injection at the elbows?)
If there is a restriction and a lot of steam your rubber exhaust hoses may be about to burn through from uncooled exhaust. Dangerous.
Do you have all RWC , 1.2 FWC or full FWC? If 1/2 or full FWC, does the exhaust smell of coolant?
How old are RWC pump impeller, manifolds and riser/elbows?
Minor "steam" in the exhaust will normally appear on cold or perhaps rainy days.
Edit: whoops , Bill K types faster!
Feel the Riser/elbows -are they quite hot so you cannot keep your palm on them indefinitely?
Is the exhaust noticeably louder than usual (not quieted by proper RW injection at the elbows?)
If there is a restriction and a lot of steam your rubber exhaust hoses may be about to burn through from uncooled exhaust. Dangerous.
Do you have all RWC , 1.2 FWC or full FWC? If 1/2 or full FWC, does the exhaust smell of coolant?
How old are RWC pump impeller, manifolds and riser/elbows?
Minor "steam" in the exhaust will normally appear on cold or perhaps rainy days.
Edit: whoops , Bill K types faster!
I CHANGED THE RISERS AND MANAFOLDS AND IMPELLERS IN THE FALL. THERE NOT HOT TO THE TOUCH. I EVEN USED A INFERED GUN AND THE TEMP WAS OK. I DO HAVE ANOTHER PROBLEM AND ITS WHEN I'M AT IDLE THE TEMP GOES UP ON MY PORT GAUGE TO 210 DEGREES BUT WHEN I BRING UP THE THROTTLE THE TEMP GOES DOWN TO 180. I THINK THIS COULD BE MY GAUGE.ANY IDEAS
370 Motoryacht
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You could have pieces of an impeller stuck somewhere. It sounds like there is some sort of cooling problem if you bring up the rpms and it cools down. I would check the impellers again.
I like to think of my cooling system as a whole. All the parts have a shelflife and I tend to treat it as a system. The last time I gave significant attention (other than impeller changes) to my system was about 4 years ago. For me, that's about my expected life between overhauls. Here's what i'm doing: (this weekend in fact)
1.) Rebuild the raw water pumps (bearing and seals)
2.) Pulled the exhaust hose off the risers and clean out the "shower heads". The raw water enters the exhaust in a series of holes around the perimeter of the riser outflow so as to evenly disperse the water. I already found about a quarter of the holes plugged. They are small, so it does not take much.
3.) Inspect the risers themselvs. They are 4 years old cast iron, so I'll probably plan on replacing after next season.
4.) This weekend the end caps come off the heat exchangers and they will be rodded out. With any luck I'll be able to do it in place, as I can't slide the tube bundle cores out of the heat exchangers without dismounting then entire 80 pound units, and that's a major pain. The cooling tubes need to be fully free of concretions and debris and after 4 years, I'll find quite a bit of crud in there when they come off. Gaskets were ordered on Monday and arrived yesterday.
5.) Time to replace the coolant (antifreeze in the blocks)
6.) Inspect all the hoses (all changed 4 years ago, should be fine).
This pretty much brings my entire cooling system up to date, tip to tail. Other than impellers which may not last 4 years, i don't like to go through them piecemeal. I find that at the end of 4 years, all parts of the system need one degree of attention or another. End of last season, my starboard engine was starting to show telltale of more steam than usual. The shower head plugs would be enough on its own, but I suspect the heat exchangers themselves will show a need for attention.
In your case, the high temps at idle suggest a plug in one or more locations. Check for a) plugged intake screen, b.) missing pieces of the impeller (if you don't automatically chase down every single tiny piece missing when you change them, they go to the heat exchanger) c.) old zincs plugging the h/e d.)hoses collapsing on the inside (hard to see this happening, but suspect ANY old hose). d.) The risers themselves or the shower heads if your riser outflows are small (mine are about 1/4 diameter).
Good luck. Gotta love spring commissioning.
1.) Rebuild the raw water pumps (bearing and seals)
2.) Pulled the exhaust hose off the risers and clean out the "shower heads". The raw water enters the exhaust in a series of holes around the perimeter of the riser outflow so as to evenly disperse the water. I already found about a quarter of the holes plugged. They are small, so it does not take much.
3.) Inspect the risers themselvs. They are 4 years old cast iron, so I'll probably plan on replacing after next season.
4.) This weekend the end caps come off the heat exchangers and they will be rodded out. With any luck I'll be able to do it in place, as I can't slide the tube bundle cores out of the heat exchangers without dismounting then entire 80 pound units, and that's a major pain. The cooling tubes need to be fully free of concretions and debris and after 4 years, I'll find quite a bit of crud in there when they come off. Gaskets were ordered on Monday and arrived yesterday.
5.) Time to replace the coolant (antifreeze in the blocks)
6.) Inspect all the hoses (all changed 4 years ago, should be fine).
This pretty much brings my entire cooling system up to date, tip to tail. Other than impellers which may not last 4 years, i don't like to go through them piecemeal. I find that at the end of 4 years, all parts of the system need one degree of attention or another. End of last season, my starboard engine was starting to show telltale of more steam than usual. The shower head plugs would be enough on its own, but I suspect the heat exchangers themselves will show a need for attention.
In your case, the high temps at idle suggest a plug in one or more locations. Check for a) plugged intake screen, b.) missing pieces of the impeller (if you don't automatically chase down every single tiny piece missing when you change them, they go to the heat exchanger) c.) old zincs plugging the h/e d.)hoses collapsing on the inside (hard to see this happening, but suspect ANY old hose). d.) The risers themselves or the shower heads if your riser outflows are small (mine are about 1/4 diameter).
Good luck. Gotta love spring commissioning.
steam is either insufficient raw water or improper mixing. your gauge is fine the cooling is not. did you have the problem before changing the risers? Are you sure you used the correct gasket with holes in the correct places.