Conference vicki::boats

    
    
    If you have not replaced the pump before, and if the motor was put up
    without being flushed out ( read corrosion/deposits in pump housing)
    the pump is probably gone.  Check the water inlet screens to see if
    they are clear, but you would hasve a worse problem at higfher rpm if
    that was the case.
    
     If it were mine, I would pull the lower unit and inspect /replace the
    pump as that is the most likel;y culprit.
    
     I got in the habit of repalcing my pump in my outboard every two
    years, I simply got tired if a pump going ion the middle of the season
    and all the inconvenience. I always do my own work, but I can more
    easily deal with frozen bolts/incorrect parts/the one additional part I
    need. etc when the boat is on a trailer in my yard, rather than at the
    slip in the marina.
    
     I'd make bets on the pump. I doubt wether a motor that new would
    have the passages plugged with corrosion. More likely the pump impeller
    has gone.
    my 2�
    
     Dick
    
    
     

    I checked it out again last night when I got home and I cannot see
    any screens that would be plugged.  If I were to drop the lower
    end to get at the pump will I run into a problem of needing special
    tools???  I also put the garden hose on it and ran it for a few
    minutes.  It appeared to be intermitent at all RPM's  would that
    still point to the pump??

    shove up metal coat hanger up the tube gently, at times these 
    
    get clogged. i've done this at leat 25 times, if after the first
    
    time it does not work do it again. the assumption here is that
    
    it has been used is salt water. its the salt your actually clearing
    
    out here.
    
    always check the simpe stuff before you go to far.
    
    jim.
    
    

    
    I'm not familiar with the newre Mercs, but pulling the lower unit on my
    old Chrysler and innumerable Johnson's wasn't that big of a deal. On
    the Chrysler- it was one shift rod ( cotter pin) and 7 bolts- 
    once the lower unit was off, the water pump was right there.
    
    If I ever got to that point , i automatically changed the impellor
    on the pump. I always kept one pump kit (
    housing/impellor/bushings/gasket) and a spare impellor on hand. 
    
     If all that looked good, then I checked the water tube from the pump
    to the engine. I had an old Merc 40 horse that used to drive me nuts.
    The tube from the water pump to the power head went through a rubber
    bushing. I would get corrosion around the outside of the bushing and
    this would build up,compress the bushing and shut down the water supply
    yo the block. I would check this tube also once the lower unit was off.
    
    
     Merc has had a lot of changes- I would get myself a manual ASAP ( most
    dealers, book stores, marine supply houses carry after market manuals).
     
    As i recall, the merc is a little tricky getting the shift mechanism
    back correctly after the lower unit has been off.
    
    
    CAUTION!! when reassembling- clean up the bolt threads and put the
    recommended sealer on the threads.In salt water , the aluminum will
    corrode if salt eater gers to it, seize the bolts and next time you
    will be looking at 7 broken bolts and a BIG reapir bill to remove the
    lower housing and drill and tap those bolt holes.
    
     Checking the tube as recommended in .3  I suspect will require
    removing the lower unit. Once you go this far-check the pump and the
    tube. Since you have it torn down- replace the pump it's cheap
    insurance. If the tube is plugged- foind out why- I'd bet it is the
    bushing.
    
    
    Dick
    
    

    Moved by moderator.
    
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Note 998.0                     Intermitten Problem                       1 reply
NEMAIL::EAGAN                                        14 lines  22-JUN-1992 09:48
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    	We have an itermitten problem with a merc 172hp outboard..
    In the last two weeks the overheating alarm (I think that's what it
    is) has gone off twice.. Saturday we Skied for about 4hrs. with
    no problem!! Sunday just skimming across the lake at about 4800rpm
    the alarm went off.. We let it sit for about 5min and restarted with no
    problem.. It seems to be pumping water fine.. It is pouring out of the
    rear just fine.. Is it possiable to have an intermitten water pump?
    The oil has been checked in the lower end.. I didn't tkae the cover 
    off the engine, but just feeling the outside it was fine.. Not
    even really warm!! Any suggestions...
    
    
    

    Moved by moderator.
    
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Note 998.1                     Intermitten Problem                        1 of 1
STEREO::CHACE "My favorite season is getting nearer" 20 lines  22-JUN-1992 10:01
                        -< Better find out what it is! >-
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      You could be picking up weeds or pieces of plastic bag that
    temporarily block the water intakes or the warning alarm may be faulty.
    I have never heard of an intermittent water pump, but you never know I
    suppose.
       This is not the kind of thing you want to let go. You need to
    find out what is going on. Holding your hand on the outside of the
    cover is useless since the engine is water cooled and the cover even
    has insulation on the inside (For noise reduction). The time to check
    is just when it happens. See if water is pouring out *then*. Take the
    cover off and hold your hand on the side of the cylinder. It should be
    hot, but you should be able to hold your hand on it for a short time.
    (temp should be about 130-140). There are various temp sensitive strips
    and other indicators to tell what the actual temp is for testing
    purposes.
      You don't want to let it go. If it really *is* overheating, the next
    time it does it (or any time it does it) it could seize and THAT is not
    fun because it means a powerhead rebuild or a new powerhead.
    
    				Kenny

    
    id try replacing the temp sender.
    
    also there are two heat ranges in the senders check you have the right 
    one for the heads you are running.
    
    i think it is something like 
    
    if temp sender is in the middle of the head its a lower range than 
    if the sender is in the top of the head.
    but dont take my word on that check which ones correct.
    
    also how high are you running the motor if its raised you may
    not be picking up enough water when on the plane
    unless you have low pickups.
    
    the other reg
    

    
    	I took the boat out of the water and brought it to the marina..
    It was bought used and had a 30day warranty.. It seems to be pumping
    water fairly good so the sending unit is a good possiability...
    I will let you know what they find... 
    
    Ron

    
    	They found a corodided diaphram in the water intakes..
    I am not exactly sure were it is.. The water flow was restricted
    causing overheating at high RPM's.....

    A corroded diaphragm in the water intake?  Huh?  Sounds like 
    typical dealerspeak, especially since the boat is under a 30
    day warranty, which their trying to reach without spending
    a lot of money on warranty repairs.
    
    I'd continue to watch for this problem, and insist on a copy
    of the repair order which documents that the problem first
    occured while the boat was still under warranty.
    
    Rick

    
    	Understand my girl firend called the marina!!!! This is second
    hand info!!!! They did say they needed parts.. You can make the 
    engine overheat on demand.. run it at about 5000rpm for about 
    5min BINGO the alarm goes off...... This could mean a corrodid
    water pump impeller!!!

    
    	I checked out the diagphram.!!!! I couldn't find any thing WRONG!!f

     	 It turned out to be the water pump and a few associated parts...
    It runs fine.. In fact quite a bit better then it did before it got
    repaired... It goes like a violated ape!!!!
    
    Ron