How hot is too hot?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=36361
Printed Date: November-17-2024 at 5:42am
Topic: How hot is too hot?
Posted By: DayTony
Subject: How hot is too hot?
Date Posted: June-16-2015 at 8:42am
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I'm reading all of these posts about thermostats and overheating. and now i'm looking at my gauge and I'm confused. While running My 351W (closed loop fresh water cooled) at WOT i typically run about 180-200 which to my understanding is normal. and she will make her way down to about 160 after it is held at idle speeds for a bit. Now most of the posts i'm reading are for raw water cooled engines. I wouldn't think there should be a difference in the temps that the engines are going to run between a raw water cooled vs fresh water cooled.Seems like I am missing something. ------------- 1988 Barefoot nautique-454 |
Replies:
Posted By: LeftFieldEngineering
Date Posted: June-16-2015 at 10:43am
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Tony, from what I've read the FWC motors run a little bit hotter then their RWC counterparts. I've found running temps for both motors, but have had no luck finding the "too hot" temp. Perhaps when the experts chime in they can get us a too hot number for both FWC and RWC motors. Also, (not to thread jack): I was thinking of documenting different temps in relation to what it says on the gauge. Ex.: Condition = Post warm-up idle Gauge Temp = 160 IR reading @ temp sensor = 140 IR reading @ circulator pump = 143 IR Reading @ top or right riser = 100 IR reading @ top of left riser = 101 Condition = Post barefoot, idling to cool down Gauge temp = 180-200 (guessing between lines) IR reading @ temp sensor = 165 IR reading @ circulator pump = 125 IR Reading @ top or right riser = 125 IR reading @ top of left riser = 123 I've noticed that at some of my highest gauge temps, the circulator pump readings are considerably cooler. I attribute this to a properly working thermostat, it's opened up allowing lake water to cool the motor. The temp sensor just happens to be at the highest spot so it's seeing the hottest water after its been though the block. |
Posted By: shierh
Date Posted: June-16-2015 at 11:14am
| 200 is pretty hot. all my heat exchange engines never ran over 180. you may want to add an oil cooler if it doesnt have one already. Heat exchangers also need to be cleaned out once in a while. acid washed to remove scale. for a lake boat i would use vinegar. |
Posted By: Hollywood
Date Posted: June-16-2015 at 11:27am
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i'm not a FWC expert but i would think a constant 180 is ok but dips down to 160 indicate something isn't right. if the engine has the ability to run 160 then i'd only expect to see 180 on a long hard run ------------- |
Posted By: Mountain Man
Date Posted: June-16-2015 at 4:44pm
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Tony: The RWC engines run lower temperatures by design, specifically the engine thermostats open at lower temperatures. At temperatures greater than 145F the dissolved minerals and metals will begin to precipitate out of solution (the raw water) and will foul the cooling jackets in the engine, risers, and manifold. This is especially important on RWC engines that have salt water exposure with their higher mineral and metal contents. Modern engines have NO problems with a constant 200F if that is the max temperature you are seeing with your FWC system. I would not want to see it any higher and if so, check your RWP impeller and your thermostat. Steve |
Posted By: 8122pbrainard
Date Posted: June-16-2015 at 7:59pm
You are forgetting a FWC system is pressurized just like a car or truck. Why? it's to keep the coolant from boiling over 212 (sea level)! What temp is your car running at!  ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: DayTony
Date Posted: June-16-2015 at 10:10pm
this is why i dont see any issue with it running at 200* but had to question reason after reading a lot of the recent posts about overheating issues. and seeing what people were worrying about. But i never really thought about the whole RW cooled engines not having a pressure bottle like the FWC ones or the possible breakdown of minerals in the water. that all makes sense now. 160* thermostat on the FWC or 140*? ------------- 1988 Barefoot nautique-454 |
8122pbrainard wrote:Posted By: shierh
Date Posted: June-17-2015 at 10:25am
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Several things to look at when running hot water flow is number one and it can be water pump and or exhaust risers and elbows. Heat exchangers can have a build up of scale inside the water jacket side that can also prevent efficient heat transfer. too lean a/f mixture can also raise temp. I would pull risers and elbows and acid wash in pool acid, will remove bulk of the rust that may be clogging the water flow. Would next pull heat exchanger and also acid wash it. would use vinegar and let it soak for a few hours in it. less aggressive than pool acid. will not damage the thin brass. Would also look at raw water pump. Is wear plate in good shape? is back of housing in good shape, impeller etc. Lastly yours will have transmission cooler but it may not have oil cooler. I recommend oil coolers. My Crusader 454's in my big boat never ran hot, i maintained the cooling system as described and also it had both transmission and oil cooler.. Inspect spark plugs for proper combustion a/f mixture. |
Posted By: 8122pbrainard
Date Posted: June-17-2015 at 8:01pm
I highly recommend solutions designed for the job. Tube in shell acid cleaners are inhibited. Most plumbing supplies carry it. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: DayTony
Date Posted: June-17-2015 at 10:06pm
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I didnt use the boat much last season so i dont recall it getting too hot. I did notice a crack in the strainer cover so i ordered a new one today, that should be her tomorrow. and i have some new wire reinforced coolant hoses coming to replace a few that look like they might be restricting flow. I'll report back if it makes any difference but for the meantime 200* is acceptable to me. so i guess any improvement will be an extra improvement. ------------- 1988 Barefoot nautique-454 |