Conference vicki::boats

    
    To test the guage, remove the wire from the sending unit,
    and touch any good ground, it should peg the needle,
    
    if this doesn't happen use an ohmmeter and check the wire for
    any breaks, if the wire checks out, then the guage is questionable.
    
    One question,  does the sending unit, match the temp guage.
    
    Example,  lets say you have Teleflex guages, you would then need
              a Teleflex temp sending unit.
    
              You can't mix and match these, they won't work or will
              give you a BOGUS reading...
    
    JIm.

    
      As .1 said, you may have a mismatch between the guage and the sending
    unit. You also may have a high resistance somewhere in the wiring from
    corrosion or such. 
    
       You should know that raw water cooled I/Os typically have 160 degree
    thermostats, so your reading will tend to be low anyway, but if it
    really IS 120, then that is way TOO low. 
    
       It is also highly possible that your thermostat is sticking partially
    open. That would cause what you are seeing and is rather common in
    boats.
    
      You need to find out if your engine temp is really 120 or not. Then
    you can direct your attention to the correct area. If you can get a
    thermometer with a remote probe that goes high enough, you can lay the
    probe against the manifold right over where the water passes and cover
    over it with cloth. You may be able to get a fair reading then. Try
    this.... can you hold you hand on the intake manifold over where the
    water passes after the engine has been running for some time?
    
      Your reading should Not be affected by how much the sending unit is
    threaded into the manifold. (The whole manifold should be the same temp
    as the water - at least where the water passes through it)
    
    				Kenny

    My guess is your thermostat is stuck open. I have a Chevy V6 that ran
    at 165 degrees with the thermostat. I had a valve burning problem and
    for some reason the mechanic decided that to help eliminate the problem
    to take out the thermostat ( don't understand the logic behind this).
    The engine runs a 120 degrees without a thermostat and it has been at
    this constant for four years now and doesn't seem to have any adverse 
    effect on the engine yet.
    
    						gary c

    The reason that I replaced the sending unit was because the gauge
    didn't seem to be moving at the end of the season two years ago
    (last time it was in the water).  I figured that changing the sending
    unit was cheap enough to try and isolate the problem.  The manifold 
    gets very warm but not hot to the point that I would have burnt my hand
    the other day adjusting the carb.  Should it be so hot that I can't
    touch it?  By the way, 120 degrees is the middle of the temp gauge.
    Wouldn't they use a gauge that would put the normal temp range in the
    middle?  I'm not even sure I have a problem, yet.  It just makes me
    wonder how it can stay so consistent.
    I will check the gauge by grounding the wire and ohm out the circuit
    this weekend.  I'll also give the parts store a call to find out if
    there temp sending units are universal or gauge specific.  There parts
    book doesn't give you choices like what type of gauge are you using,
    ect.  The gauge is 26 years old as is probably the thermastat so 
    anything could be wrong.
    Wayne

 re 995.4

> The reason that I replaced the sending unit was because the gauge
>    didn't seem to be moving at the end of the season two years ago
>    (last time it was in the water).  I figured that changing the sending
>    unit was cheap enough to try and isolate the problem.  The manifold 
>    gets very warm but not hot to the point that I would have burnt my hand
>    the other day adjusting the carb.  Should it be so hot that I can't
>    touch it?  By the way, 120 degrees is the middle of the temp gauge.

	Ooops, mine get about coffee cup hot, I could rest my hand on a mainifold
for a few seconds without getting "burned", maybe a red spot if I used the back
of my hand for > 5 seconds.  I think yours are WAY too HOT !

>    Wouldn't they use a gauge that would put the normal temp range in the
>    middle?  I'm not even sure I have a problem, yet.  It just makes me
>    wonder how it can stay so consistent.

	Well, I was wrong on the fuel gauges, but my guess is that the gauge
is an ohm_meter and the sensor (not "sender" (-: ) is a variable resistor.
Someone somwhere must have the temp/resistance curves for these things, still
guessing I'd research it at the local NAPA parts counter, likely there's a
resistance/temp curve for common GM V8s and another one for FORDs 


	If your gauge reads 120  "all the time",  i.e. when the motor hasn't
been run for a few days and the outside temperature is in the 60's you 
probably have a wiring problem..... like its connected to the oil pressure
sensor or the nav lights (-:   or its a bad gauge.  Similar approach to fuel
gauge trouble shooting, check it as an ohm_meter to ground using nominal
resistors.

	 I think your hot motor is much more important than the gauge reading
though - I'd work on that first.   Can you feel the pick-up pump housing and tell
that there is lake water temperature water in there ?   How hot does the
thermostat housing get ?   Do the pipes (or hoses) to the manifolds feel
"lake water temperature cool"  ?  etc.    Watch out you don't get your hands in
the belts if you decide to feel around with the engine running - I recommend
AGAINST it, but some people do it....

	Reg

   I will check the gauge by grounding the wire and ohm out the circuit
    this weekend.  I'll also give the parts store a call to find out if
    there temp sending units are universal or gauge specific.  There parts
    book doesn't give you choices like what type of gauge are you using,
    ect.  The gauge is 26 years old as is probably the thermastat so 
    anything could be wrong.
    Wayne

	Wayne,
		If the gauge starts at the bottom and advances to the middle 
	you must be reading some current. All you need to do is calibrate it
	somehow. 
		If this is the case I'd just put in a new thermostat and 
	see if the temp gauge reads a difference. (Not much work or cost.)	
	If the gauge reads approximately what the thermostat is rated at
	you're home free. 
		If nothing happens then the plot thickens, but lets eliminate 
	the simple stuff first.

	Paul	

    Actually, Reg, my engine doesn't feel hot at all.  I had it running in
    my yard for half an hour while I adjusted the timing and carb.  I was
    running water from a 30 gallon trash barrel thru a 1.5 inch hose and
    then into the water pick-up hose.  I could touch the intake manifold
    without burning myself.  
    
    I called the auto parts store.  They sold me a temp sensor compatible
    with Ford auto gauges of the mid-sixties.  They said to find out who 
    manufactured my gauges because I may need a different sensor.
    
    And no, I did not connect the temp sensor to the oil gauge!  Of course
    I can't figure out why turning on my newly installed bilge blower
    causes the boat to go into reverse but that's another problem. (-:
    
    Well, thanks for all the advise.  I'll do some more checking this
    weekend.  Time to do a final alignment of the prop shaft and take her
    for her first cruise in two years with the new tranny.  Wish me well!
    Wayne

	Sorry, I just re-read your .4 - first time through I thought 
you said it was hot enough to burn your hand while adjusting the 
carb...

	Write a thousand times;  

"I must read notes thoroughly and sort out the meanings of all 
multiple negatives, whether written or implied, before forming an 
opinion and entering my reply"  

.-1 x 999

	Reg

    my '91  chapparel has a volvo-penta v6 and it never reads over 120
    degrees also.  i am just about ready to check the thermostat.  i think
    they need to run in the 160-180 range.  am i wrong?  this one has been
    like this since new.
    
    steve

    If you don't have the resistance/temperature data for the the sending
    unit you can always put it in boiling water where it should read 212.
    One problem might be that if the SU is a dry sump model it should
    be all the way in to read properly...

    Opps! I just realized that I replaced a Boode (sp? or is it Boose?)
    gauge with a Teleflex. Anyone know how far off the meter might be?
    Enough that I should care and go back for a sending unit as well?

    Well, here's the latest update.  The gauge is now working or at least
    moving.  (Note: I have not changed anything as of the other day.)
    When I first turn the key on prior to starting, the gauge immediately
    rises to 120 degrees.  I left the boat running at the dock for about 
    15 minutes and it rose to 160 and stayed there for awhile so I figured
    it decided to fix itself rather than let me tamper with it but when
    I took the boat for a ride the temp rose to a shade under 240 when
    at headway speed and would drop down to 220 when at speed (maybe 25
    MPH).  I did not run it at full throttle to see what it would do
    because I want to break in the rebuilt tranny first.  Am I chancing
    ruining the engine at 220+ degrees if the gauge is reading correctly 
    now?  I can probably locate a thermastat to replace the old one but
    it may be more difficult to find a replacement waterpump if that is the 
    problem.
    Wayne

    
    If the guage is right, (i sure hope not) STOP...
    
    When you turn on the key, the guage should be at 0 not 120...
    
    I would get a compatible sending unit, before doing anything
    else.....
    
    
    JIm

Wayne:

I had the same temp gauge windshield wiper effect with my '65 Mustang a while
back.  I am of the opinion that the water circulation system in our motors is
inadequate to the task of keeping both the engine and exhaust manifolds cool
during normal operation.  You may have noticed that later model boats have both
raw water and engine water pumps (my uncle has a 302 in his '76 Ski Tique that's
set up like this, so the single-pump scheme hasn't been around for quite some
time!).  There's no bypass mechanism for the thermostat, so if it's stuck, you'll
likely blow the motor before realizing you're overheating!

What I found I had to do was restrict the flow of water from the raw water pump
to the exhaust manifolds in order to pump more water into the block.  I did this
by inserting plastic disks with a small hole in it (about 1/8") into the hose
that runs from the raw water pump to the exhaust manifold riser.  Now just where
did I find these disks, you ask?  Well right here at DEC! They are the old hard
plastic pseudo-velcro-like pads used to attach the front bezel of PDP-11/23's.
It turns out that they are just the right size to fit into a 3/4" I.D. hose, but
they won't fit into the inlet of the exhaust riser.  I probably still have a few
if you need some.

...Roger...

    Sounds like I need to do two things right away, get a compatible
    sending unit (why did I throw the old one away?) and throw the
    thermastat in a pan of hot water to see what it does.  I believe that 
    the pump whould be sufficient to cool it as I was doing some heavy
    water skiing with the boat three years ago and the temp was fine then
    until the end of the season.  So, 240 degrees is definetly the danger 
    zone, huh?  g, I'm familiar with the pop panel hard plastic disks
    that you refer to.  I will check our expendables stockroom at NIO but
    I doubt we still use them anywhere.  If you should find two, please let
    me know.  I may need to take you up on your offer.  Is your water pump
    a "Sherwood Bronze" (that's all the marking I can see) that is mounted
    to the front engine bracket below the crankshaft dampner/pulley?  If
    yes, does someone sell them now or is there a rebuild kit available?
    I can't find a similiar looking pump in any of my catalogs.  It's
    leaking a little when the engine is running but I don't think that it's
    bad enough to be causing this problem.
    
    Now, let's see.  If the gauge starts at 120 and goes to 240, I get to
    subtract 120 from 240 which means I'm really at 120 so I can take
    another boat ride today without destroying my engine (-:
    
    Wayne

    
    Sherwood is still around. DiPietro-Kay in Rocky Hill Ct. is a 
    distributor for them.  800-243-1786. I would call DK and ask
    for Sherwoods phone #.
    
    On subtracting the 120, i would tend to agree. You can tell
    by put your hand on the hoses and manifolds. You should be able to
    touch themm with scalding your hand.
    
    The old sending unit you had would not have done much good.
    You just need to know who made the guage.
    
    Now who made the guage.....??????
    
    Jim.

Wayne ... if you find out about a replacement pump let me know.  By your
description, mine is the same pump.  I think mine is OK (no problems yet) but I
never done anything to that pump in the 12 seasons I've had the boat (this one's
gonna be #13).  And it looks like it's *never* been touched, so that means the
whole shootin' match is 27 years old.  Somethin' must be gettin' tired in there!

I'll check my "miscellaneous hardware jars" tonight and see if I was bright
enough to grab several of those "water restricters" ...

...Roger...

    Roger, I'll call Streeter Marine out in Michigan where I obtained my
    Interceptor 221, 260, and 289 service manual.  He sells replacement
    parts for these engines.  
    Wayne 

    Thanks, Wayne.  I look forward to any info you can dig up.
    
    Well, guess what?  I got my machine wet this weekend and my temp gauge
    started to act a little funny.  Just a nice leisurely cruise had the
    temp up to 180.  Hmm ... let it cool down, then took it for a couple of
    tubing runs ... seemed OK.  Very strange.  Guess it had to flush the
    anti-freeze residue out of the water jackets!  :-)
    
    ...Roger...

    Wayne, do you happen to know anything about rebuilding that pump?  Or
    at least how to replace the impeller?  Or if the impeller is
    replaceable?  My pump isn't leaking or anything, but I figure that
    impeller must be kinda shot by now.
    
    On a somewhat related note, when I had the motor out of the boat last
    year I tried to turn the water inlet pipe so that the hose connecting
    the thru-hull inlet to the pump wouldn't have to make such a drastic
    turn.  I failed miserably.  And I used a big pipe wrench when I
    attempted this.  Oh well, that's why flexible hoses exist!
    
    ...Roger...

    Roger, my manual is a photocopy of the original Interceptor Engine
    repair manual.  It is very detailed.  You could rebuild the engine,
    tranny, or any accessory (including the water pump) assuming that you
    can find the parts to do it.  I will find out if the parts are
    available.  The impeller should come out by only removing two screws
    after you "press-off" the water pump pulley.  Does your's "bolt to the
    oil pan"?
    
    This morning I did some more checking.  My gauges are from the old
    "No Name" company so that is not going to help me determine if the
    sendor (not sensor) unit is compatible or not.  I noticed this
    morning that while sitting at the doc running about 1200 - 1500 RPM
    the temp stayed normal (about 160 degrees).  As quickly as I could
    idle back to 600 RPM the temp gauge would shoot up to 220/240.  I
    can't believe that the engine really gained 60 - 80 degrees in a matter
    of seconds.  bringing the revs back up would bring the temp back down
    but not as fast.  Any more thoughts out there?
    Wayne 

    
    Wayne - You're right, the engine can't lose or gain temp *that* fast.
      That makes it sound like an electrical problem.
    
    				Kenny

re >  <<< Note 995.22 by STEREO::CHACE "My favorite season is getting nearer!" >>>
            -< There's not much to those gauges, check electrical >-
    
>    Wayne - You're right, the engine can't lose or gain temp *that* fast.
>      That makes it sound like an electrical problem.

	agreed, butt.....

	I'd bet that *_VERY HOT_*  water around the senser can be 
replaced by  *_VERY COLD_*  water that fast.... once the pump starts 
to pump the way it should (-:
    
>    				Kenny


	Reg

    Could the temp sender be air-bound?  Like if it doen't extend in to the
    hole enough to touch the water, there could be an air bubble there,
    especially if the sender goes in to the top of the intake manifold. 
    You could start the engine, loosen the sender to bleed off the air, and
    retighten it.  I know this can happen in some car engines.  
    
    Carl

    I will second the air bound problem.  Replaced all the coolent in a 
    merc freshwater cooled engin this year.  First time I started it.
    The temp gauge did not move until (I guess the therostat opened) then
    it shot up to 240. Let it cool then filled it again.  Took three cycles
    to purge all the air.  The thermostat may be sticky and when the engine
    is run at speed the water pump has enough force to push open the stat
    but it may close again at idle. 
    
    
    Fire alarm I have to go
    
    KC
    

    I have a raw water cooled system so I would assume that the water would
    drain away each time I shut the engine down since there is no pressure
    once the pump isn't turning.  I'm going to take out the thermastat this
    weekend and test it.  I hope that's the problem because according to
    the guy out at Slater's Marine in Ohio (not Streeter's in Michigan) the
    pump on the old Interceptor motors are no longer made.  He said that he
    might be able to rebuild it if he can find some parts around to fit. 
    I'm going to place an ad in the Century Boat Owners Mag to see if I can
    locate someone with spare Interceptor parts around.  I don't want to
    convert to a modern pump because I've managed to stay 99% original so
    far (only the starter motor has been changed to a more modern Motocraft
    unit.)  The pump looks to be easily rebuildable if I can locate an
    impeller for it.  
    Wayne

    
    In the case of a fresh water/antifreeze system. If you replace the
    antifreeze/water mixture.
    
    Pour in the mixture as you normally would. Run the engine for
    a while. Let it cool, and remove the temp guage sending unit,
    (any air will rise to this point), bleed off the air, reinstall
    the sending unit, and refill.
    
    Its a little easier this way.
    
    JIm.

    Well, I've decided to use the replace/rebuild everything that may be
    bad approach starting with the water pump.  As it turns out,
    DiPietro-Kay carried the rebuild parts needed for my water pump.  I
    bought a new impeller and some other interesting looking items
    (o-rings, a thing with a spring attached, etc.).  My only problem is
    that I can't get the pump totally disassembled because I can't get the
    woodruff key out of the shaft.  I tried placing a screw driver on the
    leading edge and hitting it with a hammer.  The key will not move.  Is
    there a trick to getting it out?  The other way to do it would be to 
    use a gear puller to take the pulley off of the other end of the shaft
    but then it would have to be pressed back on.  I would prefer not
    having to bring this to a machine shop.  Would heat loosen the key?
    Thanks, Wayne

    Heat might help, but go easy; use a heat gun rather than a torch, try
    to apply more to the shaft than the key, and use penetrating oil, then
    use a drift or a screwdriver with a hammer.  Safety glasses are
    recommended.
    
    Overheating the shaft can weaken it significantly.
    
    J

    My boat now has a "matched" gauge & sender for temp. I also added a
    160deg. thermostat. WHat I noticed is that the housing for hte
    thermostat has lost (or never had?) the lip for the thermostat to sit
    in.Anyway, the engine still will run between 120 and 140.
    
    Should I be concerned?
    

    
    Concerned for what is the question. Not reaching running temp
    won't hurt the engine.
    
    It might affect performance, as the fuel may not atomize properly
    when it reaches the cylinder. Or the choke won't open all the
    way due to decreased temp.
    Your fuel milage may not be as good for the above reasons.
    
    Damage to the engine, kinda doubt it.
    
    JIm.
    

    re: .-1
    
    I usually respect your opinion on mechanical matters, but I had always
    learned that it was bad to run an engine under temperature as the oil
    would not circulate at the appropriate viscosity.  I believe this
    can be adjusted by changing the oil weight (although in extreme cases
    like a stuck open thermostat in sub-freezing weather (in a car
    application, of course) you might never be able to use a thin enough
    oil and in fact you would damage the engine.
    
    Right/Wrong?
    

    But what's under temperature? My guage reading averages 130-140 degrees
    in spite of a brand new 160 thermostat. Now, the housing for the
    thermostat isn't perfectly sealed where with a lip where it would
    normally seat in but it's hard to imagine thta much water flow getting
    thru when it's closed. I've asked another boater who told me his engine
    runs at similar temperature.

    The thermostat housing is an off the shelf item at any parts store -
    they're made out of cheapo white metal, and corrode away after awhile. 
    Should be less than 5 bux.  In fact, it's almost cheaper to replace it
    than the time it takes to scrape off the old gasket.  Is 160 hot
    enough?  I thought most modern engines ran at 185 -ish.  
    
    Your engine temp should be lower than the thermostat, since the stat is
    the last point before the coolant returns to the radiator or heat 
    exchanger, but I would think the difference would be smaller than you
    experience.  
    
    Carl
     

    
      Jim, you're quite right about under temperature oil. It cause even
    more buildup of acids and moisture in the oil and the oil itself has
    problems circulation if it is too cold.  There can even be a fuel
    atomization problem with too cool a thermostat (That's why a cold 
    engine needs a choke) A 160 degree thermostat is like
    bottom line for engine temp. It is likely you can get away with it
    better on a boat than a car because the engine is run under greater
    load and so would heat the oil more. I know my father's boat ran better
    and used less fuel when he went to FWC which included changing the
    thermostat to a 180 from a 160 thermostat.
    
    	I think everybody should remember that NONE of these guages or
    sending units are anything like laboratory instruments. I would guess
    anything within +- 10% would be normal for one of these guages. :^)
    
    				Kenny

    i'm still curious as to why the water tempertaure is 130-140 degrees
    when the thermostat is 160!  i have many cars which have the same
    temperature senders and guages but when the thermostat is 160 or 180
    the gauge matches it exactly.   
    
    what gives here?   are boat engines different some how since they are
    lake water cooled?
    
    very curious,
    steve
           

    I don't know...
    
    
    The engine is an original 1977 will practically all original parts.
    Brand new (matching) gauge and sensor. Brand new (160 deg.) thermostat.
    Engine runs fine as far as I can tell.
    
    Maybe I should simply leave it alone.

    You may want to check the thermostat out for being partly open all the
    time but your running in cold water and their is no radiator to build
    up the heat.I have an omc v6 and she was running like that and I found
    the thermostat stuck open a crack so the engine ran at 120f.I replaced
    it and now with that fix she now runs at 160f even when the lake is at
    37f.

    
    I think you said it all..........
    
    It runs fine, and i would leave it alone........
    
    JIm

    It would be simple enough to take the thermostat out, place it in a pan
    of water on your stove with one of those oven temperature gauges.
    Slowly heat the water and observe when the thermostat opens up versus
    the temp on the thermometer.  i strongly believe that the engine needs
    to run at the proper temp.  I had to replace the engine in my truck at
    36K miles because I lived one minute from work and for 4 years I only
    used the truck to go to work.  The oil never had a chance to heat up
    enough to properly clean the engine.  Results: clogged oil journals
    even though I changed the oil every 3000K miles.  I now have 100K on
    the truck but I live 40 minutes from work.  The new engine is still
    clean as a whistle and running great.  there should be no reason why
    your engine can't come up to the proper temp.
    Wayne

    I would like to add to the saying "If it's not broke don't fix it"
    the saying "If you're not totally sure it's broken don't even go near
    it".  I managed to break off one of my thermastat housing bolts while
    trying to take out my thermastat and test it.  Needless to say, I'm in
    more trouble now than I was before.  The combination of aluminum
    manifold, steel bolts, heat, moisture, and 26 possible years of
    corrosion firmly welded the two together.  The bolt seemed to be coming
    out very slowly but then let go.  Now I am in more of a mess because I
    will have to try and "easy-out" the rest of the bolt (and probably the 
    other that will surely break off also) and rethread the bolt holes.  If
    that doesn't work it will be new manifold time!  I used the boat last
    night with a pair of vice grips holding the thermastat housing tight.
    I've gotten pretty good with the throttle to keep the RPM's above 1000
    as much as possible so it doesn't overheat.  Rather than cause more
    damage and miss the rest of the season, I may wait until October before
    I try to fix (break?) it further.
    Wayne

    
    I;ve tried all of the penetrating oils etc. known to man.
    
    A couple of months ago, i was in COnsumer Auto Parts in Marlboro.
    
    They were raving about this new "snake oil" trade name is
    
    Break Away.  Having been bit before i hesitated. But for $2.99
    
    a spray can, what the hell.  
    
    I'll report here its the best i've ever used. It literally melts
    rust, and bolts and nuts come out real easy.
    
    I'd recommend you give it a try.
    
    JIm.

    thanks, Jim.  Now that I've got the bolt head out of my way, I can
    spray the stuff right into the bolt hole before using an easy-out.
    Do you go by there frequently?  Any chance you can pick up some for
    me?  I'll be back in your facility tomorrow, Thursday, and Friday.
    if you can't, that's ok.  The vice grips work fine :-)
    Wayne

    
    Wayne, will have it here for you friday morn.
    
    JIm.