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Impeller change on Mercruiser


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I just received an e-mail from Mercruiser Customer Service regarding instructions on how to change out an impeller on my Mercruiser Tow Sports. Basicly due to the low location of the seawater pump it is very difficult to access the backing plate bolts (down low, with several hoses and fuel line in the way). At any rate, the easiest way to get to the impeller is to pull the whole pump out.

1. Drain the seawater section of the cooling system.

2. Close the seacock valve, if applicable.

3. Remove both of the hoses from the aft side of the seawater pump.

4. Remove the serpentine belt.

5. Remove the two bolts attaching the seawater pump and bracket to the engine.

FYI, Merc enginineered the cooling system to make winterizing as idiotproof as pulling out four blue drain plugs, two of which are on the seawater pump way down low in the engine. Unfortunately, the same system requires pulling the pump for routine maintenance or busting your knuckles. I know that there is one other guy on TMC who has the same setup that I do.

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I just received an e-mail from Mercruiser Customer Service regarding instructions on how to change out an impeller on my Mercruiser Tow Sports.  Basicly due to the low location of the seawater pump it is very difficult to access the backing plate bolts (down low, with several hoses and fuel line in the way).  At any rate, the easiest way to get to the impeller is to pull the whole pump out.

1.  Drain the seawater section of the cooling system.

2.  Close the seacock valve, if applicable.

3.  Remove both of the hoses from the aft side of the seawater pump.

4.  Remove the serpentine belt.

5.  Remove the two bolts attaching the seawater pump and bracket to the engine.

FYI, Merc enginineered the cooling system to make winterizing as idiotproof as pulling out four blue drain plugs, two of which are on the seawater pump way down low in the engine.  Unfortunately, the same system requires pulling the pump for routine maintenance or busting your knuckles.  I know that there is one other guy on TMC who has the same setup that I do.

I have the same set-up, to me it is much easier to just remove the pump and do the change on the work bench, only takes me about 30 mins. total. FYI be careful not to over tighten the housing bolts, if you do the housing can and in my case will crack making a fun trip back to the boat ramp.

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FYI, Merc enginineered the cooling system to make winterizing as idiotproof as pulling out four blue drain plugs

I agree with RiverRunner... BTW: there are 5 drain plugs on the Mercruiser, 2 on the starboard side, (driver side) and 3 on the port side.

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FYI, Merc enginineered the cooling system to make winterizing as idiotproof as pulling out four blue drain plugs

I agree with RiverRunner... BTW: there are 5 drain plugs on the Mercruiser, 2 on the starboard side, (driver side) and 3 on the port side.

Where is the 3rd on the port side mine only has two per the manual, did I miss something last season?

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Thanks Skistud! I'm going to tackle this one in spring and was hoping you'd be the guinea pig. Anyone with this setup that could take some pictures with arrows, etc... pointing to everything would be real helpful.

Mike

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Thanks Skistud!  I'm going to tackle this one in spring and was hoping you'd be the guinea pig.  Anyone with this setup that could take some pictures with arrows, etc... pointing to everything would be real helpful.

Mike

It is real easy the first time I did it I used a paint marker to mark were the hoses came off and other than that there is nothing to it just don't over tighten the housing bolts, good and snug will do it.

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It is real easy the first time I did it I used a paint marker to mark were the hoses came off and other than that there is nothing to it just don't over tighten the housing bolts, good and snug will do it.

Mike,

Are you talking about the four or five bolts holding the back plate on or the two bolts that attach the seawater pump to the engine? I assume you're talking about not over torqueing the small 4 - 5 bolts.

My Merc only has 4 blue plugs - two from the seawater pump, one on the "distribution housing" on the port side down low, and one on the side of the thermostat housing.

For winterizing I unscrewed a bolt on the top of the thermostat housing, took a funnel and needed 4 gallons of -100 anti-freeze until it came out the exhaust.

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