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454 7.4 mpi l VI sea pump back flush question and help please

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454 7.4 mpi l VI sea pump back flush question and help please

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Old 06-16-2013, 10:24 PM
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454 7.4 mpi l VI sea pump back flush question and help please

Hey guys I have a 99 boss 302 with twin 454 7.4 mpi VI models with around 144 hours... Both engines have ran good around 4-5 times with no issues but today my star board engine started to run hot( prior to this temps seemed up and down, I had the beeper come on today... I noticed one engine pissing out both exhaust pipes and the engine which got hot only pissing out of one exhaust very little... I'm pretty sure it's prob my sea pumps so I have new one the way!!!! Do you all agree on that??? Also when I replace my sea pump impellers should i back flush my raw water cooling system? If so how do I do it please???
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Old 06-16-2013, 10:25 PM
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By the way it's a 99 baja Boss 302 with twin mpi 7.4s.... Please help
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Old 06-17-2013, 12:56 AM
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Pull the water hose going into the oil cooler and reach into the oil cooler to check for debris and impeller pieces.
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Old 06-17-2013, 06:20 AM
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Can u let me know how to do this ??? Please
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Old 06-17-2013, 06:21 AM
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2 hoses on the back of see pump
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Old 06-17-2013, 09:13 AM
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im installed the sea pump housing etc asap just want to know the back flush procedure etc
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Old 06-17-2013, 09:30 AM
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If your motor is the same as mine, water flow comes from transom assembly to seawater pump , then under the motor and into 2 colors on the other side along the oilpan, then at the front of the motor it makes a 90 straight up thru another cooler then the thermostat housing. When I flushed mine I separated the hose between the last cooler and the motor. backflushing from here and separating each cooler will usually get all the chunks. If your overheating only on one side, if you have something plugging it up it will be further down stream since the separation side to side doesn't start until the thermostat house. try pulling the thermostat so you get good flow thru the block.head, and disconnecting the hose that goes from the motor to the exhaust manifold and backflush from there. pull the drainplug on the boat and pay attention to the water level in the bilge as it can rise pretty quick.
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Old 06-17-2013, 09:45 AM
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Let me know saome thing? do i need to worry about flushing is the sea pump is in a whole??? only was getting warm when going 30-40 mph... When idleing it was cooling perfect
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Old 06-17-2013, 10:42 AM
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If you don't have strainers you could have sucked something up. No you don't have to flush it, you just have to be willing to buy a new motor if you cook this one because you didn't. So if your motor is worth less than 45 minutes of your time and a new thermostat gasket by all means skip flushing it.
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Old 06-17-2013, 10:59 AM
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i have been looking for picks or some thing to do this??? if the sea pump is just worn out what should i do???
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