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  1. #1

    Default Changing impellor on 4hp Yamaha

    Hi

    I just changed the impellor on my Yamaha 4 hp outboard today but had a hell of a job reassembling the bottom end to the motor seems to be hard to align the main drive shaft, cooling water feed pipe and the gear selector rod all at the same time.

    Are there any tricks to this reassembly???? to avoid me hours of frustration next time.

    Cheers

    Simon

  2. #2
    Captain JUSTINTIME's Avatar
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    Talking Re: Changing impellor on 4hp Yamaha

    practice makes perfect
    HUMAN BUILT = HUMAN FIXED
    CERTIFIED MARINE TECH

  3. #3

    Default Re: Changing impellor on 4hp Yamaha

    Simon
    I'm about to do the same
    have no manual
    can you describe what you did!
    Chris

  4. #4
    Petty Officer 1st Class Yamajoe's Avatar
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    Default Re: Changing impellor on 4hp Yamaha

    it is tricky but patience and practice will get you there

  5. #5
    Petty Officer 2nd Class matt2002's Avatar
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    Default Re: Changing impellor on 4hp Yamaha

    Try doing a impeller change on a 75 Enduro.With the boat in the water and tied to the dock .I did my water pump on a 65 Johnson back in the early 90's the same way so you might say I've had a little practice.

  6. #6
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    Default Re: Changing impellor on 4hp Yamaha

    Simon, I am having the same problem lining or getting the shaft spline lined up and put in. I have successfully done a Honda 5hp, Evinrude 18 and 15 and others. This Yamaha 4hp and also a Mercury (Nissan made) 4hp have both got me stumped and frustrated.
    It seems like the shaft isn't just directed into the spline. There must be some secret. If I don't get help here I am going to fork out some bucks to watch someone else put it in. Anyone have any tips
    Marvin

  7. #7

    Default Re: Changing impellor on 4hp Yamaha

    The following is my post a week ago for impeller repolacement on my 8 HP Yammy...

    "Well for anyone who may one day have the same problem, I discovered that when I put the motor back on the boat and gave it one more shot, that the lu went in fairly easily, because for some reason the motor needs to be titlted when reinstalling.

    The reason I took the motor off the boat was to get better access to the gear shift which is up the top of the lu in my model.

    I put the gearshift and the gear shift rod in reverse, jiggled the prop very slowly back and forward while pushing up on the lu and she went staright in.
    Now some mechanic may get it in off the boat, without tilting the motor, but I spent hours trying all combinations of things to do and this was the only way it worked"

    I will not be able to give any more info on this subject as this is all I know.

  8. #8

    Default Re: Changing impellor on 4hp Yamaha

    Forgot. There are a couple of videos relating to your yam/mariner 4 on youtube.also some on larger motors but same procedures.

    http://www.youtube.com/watch?v=ZB0zt...eature=related

  9. #9
    Petty Officer 1st Class
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    Default Re: Changing impellor on 4hp Yamaha

    I got some help from a local shop today, but they worked on it over 2 hours. I watched for a while and had to go pick up someone. One thing they did different that may have helped was to leave off the block that goes around the shift rods and put it on through the hole after the lower unit was up. This wasn't a Yamaha shop. I called a Yamaha dealer and they charge $100 parts and labor and figure 1 hour labor. There was some comfort for me to see seasoned outboard mechanics have so much trouble but next time I will get a manual and see how it is supposed to be done. If I have the same trouble I will spend $100 gladly.
    Thanks for your advice and I will use this forum again.
    Marvin

  10. #10
    Cadet
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    Default Re: Changing impellor on 4hp Yamaha

    Quote Originally Posted by matt2002 View Post
    Try doing a impeller change on a 75 Enduro.With the boat in the water and tied to the dock .I did my water pump on a 65 Johnson back in the early 90's the same way so you might say I've had a little practice.
    any tips I got a 1972 Johnson 40 hp E, I want to change the impeller where is it located? what do i have to take apart can i just change the impeller ? is that the only cooling component that wears out????


    40hp 14ft

  11. #11
    Rear Admiral
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    Default Re: Changing impellor on 4hp Yamaha

    here is a quote from tashasdaddy


    if you have a question, please post it in the Johnson / Evinrude forum.

  12. #12
    Lieutenant Junior Grade
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    Default Re: Changing impellor on 4hp Yamaha

    Put some grease on the splines and turn the flywheel by hand while pushing up on the leg

  13. #13
    Seaman Apprentice Can't Cast's Avatar
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    Cool Re: Changing impellor on 4hp Yamaha

    Simon,
    I just did a 5hp Yamaha/Mariner water pump job and had the same problem you described. The lower unit did not want to line up for nothing (seemed slightly tilted), and I couldn't get the driveshaft to hit the hole in the motor.
    The shift rod was causing it. It was a little off and was not going through the rubber bushing at the top of the housing (in front just under the tilt latch).
    I noticed as I tried to push the foot up, it was lifting the rubber shift rod bushing slightly, and the foot seemed tilted to the rear somewhat.
    I pried the bushing out with a small screwdriver, and tried again using the screwdriver to guide the shift rod through the hole. The lower unit went right in straight as can be, with no resistance. Then I put a light coat of grease on the little rubber bushing, and shoved it back down over the shifter rod top and worked the lip back in with the screwdriver until it seated.
    The job was a breeze after I pulled that bushing. Before I did, I had spent an hour with no luck and was wondering what the heck was going on.
    Maybe this will help you next time, or help someone else with this problem.
    Just pull that dang bushing, and it's a breeze from there!

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