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Starboard 454xl 350 fwc running 190-200 degrees

Jeff0101

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I have a 30 chris craft tournament. While the port motor runs 160 if pushing it runs 180. Starboard at idle stays 160 while running will goto 190-200. New impellor, new risers, new 160 stat fresh 50/50 coolant. At idle checking temps with the temp gun the manifolds run 200+ while the risers run around 80s low 90s and the thermostat housing is 160. The motor runs strong and normal. The port motor temps checked are all the same at idle except the manifolds are notably cooler 140s - 160.
Any ideas or thoughts would be appreciated. Both exhaust flow strong. I've back flushed starboard exchanger and u cooler with water then with muratic acid. I have been wondering about the water pump for the coolant idk.
 
The temp on my gauge is showing 190-200 while running while the temps on the upper manifold are hitting 200+ while idling just to help clarify
 
I have only had the boat a short while but I will be sure to do that or just replace it. I have replaced the bronze pickup screen for the port engine but not the starboard and will be doing that when I pull it out shortly. The starboard seems to be pumping as much or more then port and all 4 risers are about the same temperature but the manifolds on the starboard run alot hotter and at idle my gauges will read 140-150 port 170+ starboard while at the dock. The starboard is the counter rotation motor idk
 
I have a Crusader 8.1L. I removed the riser/elbow and flushed the outside shell (also removed 1/4" drain plugs near base) with barnacle buster...poked with copper wire...lots of crud/rust/stuff came out. Replaced with new exhaust blocking plate and gasket (used Indian gasket sealer). Before flush, elbow was 180; after flush elbow was 125. There is a tendency for the elbow furthest from heat exchanger (thus more hose and more pressure drop) to become clogged.
 
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I have a 30 chris craft tournament. While the port engine runs 160 if pushing it runs 180. Starboard at idle stays 160 while running will go to 190-200.
Nearing 200 degrees is getting close to the dangerous area.

New impellor, new risers, new 160 stat fresh 50/50 coolant. At idle checking temps with the temp gun the manifolds run 200+
200+* is very high!

while the risers run around 80s low 90s and the thermostat housing is 160.
Do you mean "elbows"? (Risers/Spacers sit between the manifolds and elbows!)

The engine runs strong and normal. The port engine temps checked are all the same at idle except the manifolds are notably cooler 140s - 160.
Any ideas or thoughts would be appreciated. Both exhaust flow strong. I've back flushed starboard exchanger and u cooler with water then with muratic acid. I have been wondering about the water pump for the coolant idk.
Have you tried "rodding" the insides of the Heat Exchanger's tube bundle? Often the interior of these tubes can become restricted with debris.

Question: are these Full Closed Cooling systems (i.e., engines and exhaust manifolds within the closed system), or Half Closed Cooling systems (i.e., engines only within the closed system)?

The temp on my gauge is showing 190-200 while running while the temps on the upper manifold are hitting 200+ while idling just to help clarify


When was the last time you put a cam in the raw water pump?
Great question!
The impeller cam is equally important! The cam is what folds and unfolds the impeller vanes.



I have only had the boat a short while but I will be sure to do that or just replace it. I have replaced the bronze pickup screen for the port engine but not the starboard and will be doing that when I pull it out shortly. The starboard seems to be pumping as much or more then port and all 4 risers are about the same temperature
Again, I assume that you mean "elbows".
Whether Full or Half closed cooling system, or raw water cooled, Elbows are always seawater cooled.
As long as the seawater pump is doing it's job and the system is not restricted, the elbows should run warm only to the touch.

but the manifolds on the starboard run alot hotter and at idle my gauges will read 140-150 port 170+ starboard while at the dock. The starboard is the counter rotation motor idk
Are both engines seeing the exact same ignition advance curve?
 
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Thanks for the responses. They are fully closed cooling systems, and yes I was referring the elbows after the blocking plate that mixes the sea water back into the exhaust. Those where replaced with new and hold at 80-90 degrees with temp gun. The boat is out so in going to take the advice and pull the water pump and either rebuild it with new cam or just replace with a new one and pull the heat exchanger and u-cooler off to have to better inspect and clean them. I also have a new bronze screen
for the intake scoop as the old is a little soft and has some bottom paint on it. For piece of mind I will probably pull the water pump on the motor and replace. My motors sit outside under boxes on the back deck making it pretty ez to get at everything. I'm no expert by any means but it just seems like the problem could be in the closed side flow. The water flow out the exhaust is strong the elbow/riser temps seem normal but manifold temps where the coolant flows gets to hot. I'll post more when I get the chance to pull the parts off and inspect. Unfortunately I wont be able to verify anything for sure until spring ha
 
I would say 95% of the issues I seen are due to the raw water side vs the closed side except for when the coolant was NOT maintained....

The U-coolers design isn't the best but you said that was flushed out.....I'd look for an air leak on the suction side, assuming the pump is serviceable....the finger on the cams will wear and the volume will be reduced. There is no accurate way of telling if the water flow is adequate other than to measure it.....

Water pumps have minor kits and major kits and there are multiple parts in their kits for a reason....until you have some history with a particular application you will be better off replacing everything provided....
 
Thanks I did back flush a gallon of muriatic acid through the exchanger and cooler with a 5gal pail and pump. I took the end caps off the exchanger to look at them and it looked pretty clean but I will def be able to inspect it better and actually look through once I take it off. I'll get the water pump off and go through it too. Thanks I'll let you know what i find.
 
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They are fully closed cooling systems, and yes I was referring the elbows after the blocking plate that mixes the sea water back into the exhaust.
Are you talking about risers/spacers.... similar to this?
shopping

Depending on the elbow (ported or not ported), the plumbing and where the block-off plates/gaskets are located, these may be within the closed loop, or they may be within the seawater loop.

Those where replaced with new and hold at 80-90 degrees with temp gun. The boat is out so in going to take the advice and pull the water pump and either rebuild it with new cam or just replace with a new one
Which style seawater pump? Belt driven or crankshaft style?


and pull the heat exchanger and u-cooler off to have to better inspect and clean them.
As for the main heat exchanger, the seawater side of the tube bundle is fairly user friendly.
However, the ethylene glycol side of the tube bundle is not!

If the closed cooling systems were added to these engines, the H/Es may have a build up of rust scale within the E/G side of the tube bundle.
If so, this would hinder their ability to remove engine heat. Much like a car/truck radiator that needs to be rodded out and cleaned!


For peace of mind I will probably pull the water pump on the engine and replace.
FYI, for engines fitted with closed cooling systems, you can save a few dollars by using the automotive version engine coolant circulating pump.
The Circ Pump will not know that it's been installed on a Marine engine!


My motors sit outside under boxes on the back deck making it pretty ez to get at everything. I'm no expert by any means but it just seems like the problem could be in the closed side flow. The water flow out the exhaust is strong the elbow/riser temps seem normal but manifold temps where the coolant flows gets to hot. I'll post more when I get the chance to pull the parts off and inspect. Unfortunately I wont be able to verify anything for sure until spring ha
FYI again..... the coolant within the engine is thermostat controlled. The thermostat holds back coolant on an "on-demand" basis, and then releases it as required.
Without seeing a schematic of your cooling system, I would say that most exhaust manifolds receive coolant that is not thermostat controlled.

I would say 95% of the issues I seen are due to the raw water side vs the closed side except for when the coolant was NOT maintained....
I would agree with Mark.

The U-coolers design isn't the best but you said that was flushed out.....I'd look for an air leak on the suction side, assuming the pump is serviceable....the finger on the cams will wear and the volume will be reduced. There is no accurate way of telling if the water flow is adequate other than to measure it.....
Agree again. A tiny suction breach will kill a seawater pump's ability to pull seawater in!

Water pumps have minor kits and major kits and there are multiple parts in their kits for a reason....until you have some history with a particular application you will be better off replacing everything provided....
Assuming that Mark means seawater pumps..... yes, replace all.
If crankshaft pumps, these are not expensive compared to other seawater pumps.
 
Try a 40%antifreeze/60%water coolant mix. It can conduct more heat than a 50/50 mix.
Try inserting a piece of clear tubing into the line feed each exhaust elbpw. If you see any bubbles at all after it's been running 10 seconds or so., there is an air leak between thru-hull and raw water pump.

If you can see them, is water flow out of each exhaust pipe equal?
 
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