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  1. #1
    Member
    Join Date
    Apr 2018
    Location
    Lebanon, TN
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    1,370

    2019 4 stroke Impeller replacement?

    I have a 2019 4 Stroke Pro XS 250.

    I have just over 100 hours on the motor. I changed the oil myself a couple of weeks ago.

    I'm guessing it's a good time to change the impeller as well. I haven't found any instructions for this online. Is it safe to just change the impeller, or do I need an entire water pump kit with new gaskets, etc?

    Is there anything to changing the impeller? Or is it as simple as dropping the lower unit and putting the new one in like you'd do on the older engines?
    2023 Puma STS

  2. Member
    Join Date
    Feb 2014
    Location
    Decatur, AL.
    Posts
    5,023
    #2
    Post your serial number. Look in your manual for info!

  3. Member
    Join Date
    Apr 2018
    Location
    Lebanon, TN
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    1,370
    #3
    2B634495

    I am the second owner of the boat. I do not have the manual for the motor.
    Last edited by TNReb; 02-04-2020 at 10:01 AM.
    2023 Puma STS

  4. Member
    Join Date
    Feb 2014
    Location
    Decatur, AL.
    Posts
    5,023
    #4
    I have 150 HP Merc 4 stroke. A 2018 model mine says recommend new impeller every 300 hours and suggest you get dealer service on it. Pretty sure you can look up your service manual online. Go to Mercury Marine and follow their prompts.

  5. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,945
    #5
    Here's the "silly skinny" on water pumps. The new 4-strokes utilize the EXACT same impeller that was used on the previous 3L model ProXS. And they spin them at the same RPM's.

    Optimax Model: Once per year or every 100 hours.

    Fourstroke Models (most): Once every 3 Years or 300 Hours.

    Now... take a look at the back of your Fourstroke where the exhaust turns and travels down into the midsection. There's a TON of plastic and rubber back there... right where things would be the FIRST to "melt down" if the water pump failed.

    Water Pumps are a maintenance item- damage that occurs due to overheating (caused by a worn or damaged impeller) is not covered under warranty.

    Hence- I would recommend you consider impeller replacement (plus gaskets) an ANNUAL/100 Hr. Item, or at the very least, split the difference and do it at 2 yrs/200 hrs.

    Recommend you have a service manual when doing the water pump. Actual removal and pump is nearly identical, BUT shift alignment and gearcase install is a bit tricky (especially since you can't touch the trim OR turn the key on during install, lest the shift actuator "park" back in neutral).


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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