Conference vicki::boats

    Being the owner of a '77 vintage boat, I've learned to live by the rule
    of simply to respect the mechanical stuff that comes with the boat,
    don't abuse it, and have it replaced --when it breaks--.
    
    I've learned that labor is the largest portion of repair bills and it
    makes little difference whether the labor is performed before failure
    or afterwards. I've also learned that marine repair labor compares with
    some of NASA's in flight repair missions so I avoid it unless
    absolutely necessary.

    I just purchased a 78 Merc 175 at the end of this season.
    
    I'd be curious as to wether there is any truth to what the dealer
    told you as well.
    
    I don;t know much about boat engines, I know a little about car
    engines.  Based on what little I know I would say the dealer is
    being pretty creative in what they stated.
    
    Anyone else care to comment?  Mark

    
      This is the most, ok, ONE of the most ridiculous things I've ever
    heard. The fact is that if a head or block was going to warp, it would
    do it when it was fairly new. Since your engine has been used a fair
    amount, you have what is known as a 'seasoned' block and THOSE are the
    VERY best kind. All the stresses put in during casting work their way
    out during all the heat/cool cycles.
    
      You probably want to decarbonize the engines using one of the readily
    availble sprays also talked about elsewhere in this file. You might
    also want to retorque the heads which is done one bolt at a time and
    requires no parts at all.
    
      That is JUSt like saying replace your car engine because it might
    have a problem later. 400 hours is not a lot of time on an outboard.
    You should get as much as 800-1000 MORE hours if you maintain them
    properly. (And no, that doesn't include changing huge parts)
    
    				Kenny

    Re: .03
    
    Ken:
    
    Why don't U say what's on your mind -- Repressing those feelings can
    only hurt!!
    
    Dennis

    Note: Standard "I am not an outboard type of guy" disclaimer in affect.
    
    I'm just wondering if the dealer was trying to advise you of the
    problems they are having with outboards "carboning-up" the piston rings
    due to poor gas quality which will sooner or later cause the piston to 
    seize and blow the motor.  I saw an example of a Merc engine piston
    that was pretty sad.  The owner had to buy a new engine.  Maybe when
    they change the power head, they replace the piston rings or something.
    I don't know.  Where's Rick Wilson when we need him?  I might be
    tempted to pull the power heads to have a look at what's going on
    inside but I wouldn't replace them automatically just because you have 
    400 hours on them.
    
    Wayne 

     
    re.04  All right - and your mother wears army boots, too!
    
    				Kenny

    
    Wayne - what was said in the opening note was that the dealer advocated
    replaced the 'heads' not the 'powerhead'. There is a HUGE difference in
    price and that was also quoted so I think its pretty sure that the
    original assumption is right. It would also be a lot more money to
    replace rings, etc when a new head was installed, since it would
    require taking virtually all of the powerhead apart.
    
      On a 2 cycle outboard, the powerhead is what amounts to the engine
    block on a car. It comprises the entire engine block casting, pistons,
    rods, crankshaft and all the internals that go with it, AND cylinder
    heads. Though they are complex castings, there are no valves of any
    kind on 2 stroke outboard cylinder heads if you don't count
    thermostats.
    
      I WOULD say that removing the heads and decarbonizing would not be
    too much of a ripoff. I say not too much because it has not been shown
    that those engines HAD a lot of carbon (Or ANY other problem for that
    matter) AND it seems the over the counter spray-in decarboning
    treatment works fairly well. Also, with the new TCW3 oils, carbon
    fouling is *supposed* to be resolved. (I'm from Missouri on that one
    though - I'll believe it when I see it. Even though that is the prime
    reason TCW3 came out)
    
    				Kenny

    
    i know my engie is recommended to have new head gaskets every 10-100
    hours however its a mod vp with crome bores.
    
    ive blown one head gasket and had one piston cracked at about 400 hrs.
    
    if only racing hours are on it they recommend rebuild at 100 hours
    however because im socialing for abot 75% of the time i dont stick
    rigidly to their recomendations.
    
    i did however go from the two peice head to the one peice head.
    and decreased compression from 80 thou shaved back to standard.
    
    it is recommended for most outboards to have the head gaskets changed
    at regular intervals,however to change the heads just for the heck of
    it sounds a bit over zealous.
    
    tks 
    the other reg
    

    I spoke with another Merc dealer and they recommended replacing the head
    gaskets. The first guy wanted to change the heads because Merc
    re-designed them and he felt there was less chance of having engine
    problems with the new style heads. The new style heads cost around
    one hundred each, so I would be looking at $400 for the heads plus
    gaskets and labor to do both engines. He estatmated $800 to $900
    for the Job. The second guy estatmated $100 for each motor to just
    replace the head gaskets. I think I will go with the second guy and
    have him inspect the heads when he pulls them.

    Unless you are having problems I wouldn't replace the heads either.
    I would re-torque them.  I believe you said you have twin engines?
    If so, safety isn't a big issue because you aren't relying on just one
    engine to get you home.
    
    I would peform normal routine maintenance, keep an eye on the engine(s)
    for obvious developing problems and 'run em until they break'.
    
    Jeff

    Any raw sea water running through or against the head or head gaskets? 
    
    If so, I'd think about replacing the head gaskets, and use the op-
    portunity to check out the pistons for carbon build up.  I would
    consider head gasket replacement a DIY job on a two stroke...and don't
    forget to retorque (or have the dealor retorque) the head bolts per the
    repair manual order after a couple hours of run time.  I'd guess the
    cost at around 50 bux for gaskets for two engines?  Add another $50 for 
    a torque wrench, which you should have anyway for stuff like changing 
    props, and such.

    I decided to remove the heads myself and inspect them. All four (two
    engines) showed signs of corrosion and one of them had already corroded
    to the point where is was letting a small amount of water into the
    cylinder. 
    
    The problem is were the cylinder is close to the edge of the block. On
    the old designed head there is a solid peice of aluminium which does not
    let water circulate. On the new style head there is a water passage at
    this point. With the old head heat will build up here which will lead
    to the corrosion problem. 
    
    I'am real glad I pulled the heads to look, If I ran them much longer I
    would have blown the power head. The new heads list at $137 each which
    is a lot cheaper then a new power head. I would advise anyone with
    V6 Mercs from the late 80s to check their heads.