Conference vicki::boats

    Check your manual. Most drive manufacturers do not recommend keeping
    the drive up for extended periods. Why keep that unnecessary pressure
    in the system? Also, the hull manufacturers usually recommend propping
    up the drive unit if you have to keep it up, ie. for transportation.
    Why? Because it puts enormous stress on the transom.
    
    If you dosn't have the rod which props up the drive (it seems that most
    people seem to lose it), then you could tie it up to a cleat.
    
    Tally-ho,
    
    Ray

    
    re .2
    
    The boat is currently on blocks.  The distance from the bottom of
    the hull to the ground is only about 1 foot. This is the reason
    why the drive is in the up position. I could lower it to where the
    drive is sitting on the ground to take the strain off of the stern,
    however there is somthing wrong. When the drive is up, it should
    stay up, and not creep down over a short period of time. Besides,
    when the boat is moored in the water, the drive will have to be
    in the full up position. The water at the dock is only about 2 feet
    deep.
    
    	In reference to .1, the check valves sound like a good place
    to start.
    
    	Dan
    

As reply .2 pointed out, the trim cylinders are not intended for holding
the drive up for long periods of time or while transporting.  Almost any
hydraulic cylinder will bleed down if left pressurized for long periods 
of time.  And the trim system is not intended to withstand or support the 
bouncing motion of the drive while trailering.

My Johnson outboard has a lever that flips down to support the motor, and 
then you hold the trim button down until the motor "locks" into place 
against this lever.  Does the Cobra drive have a similar arrangement?  If 
not, there are support rods available for this purpose.  I've also seen
various homemade supports, ropes, etc. that people have devised.

FWIW, there is manual release valve in the OMC trim systems but I doubt
it's causing your problem because you'd notice oil leaking out.  On my
88hp outboard it's located on the right side of the transom bracket, and 
at first glance looks like just a set screw that's recessed behind a 
snap-ring.  I found out about it on my motor the hard way this spring.
The power trim pump was frozen solid when I hauled the boat out of storage,
and the motor was locked in the "down" position.  After mucking around 
for about 2 hours I finally disconnected the trim cylinder so I could 
lift the motor and bring the boat into the dealer for repairs before the
warranty ran out.  The service manager asked me "why didn't you just open 
the pressure relief valve and lift the motor?", and then showed me where 
it is.  That tidbit of info is now filed away for future reference!

Rick W.

    try bleeding the system, you may have air somewhere in the
    system, you wouldn't notice any leaks, but this sounds
    like one of the symptoms. 
    
    
    
    
    Jim.

    
    
    	This is certainly not normal for the drive to come down by about
    a foot of travel over a period of 2 weeks without any movement of
    the boat. I have owned both Mer Cruiser and Volvo drives, and have
    never seen this problem. When the drives were up, they stayed up.
    	To put my concerns to rest, I called a local OMC service shop.
    They said that this indeed was not normal, and sounded like a bad
    check valve or possibly a bad ball valve in one of the cylinders.
    Since the boat is still covered under a warrantee by the marina,
    I think I'll let them worry about the repair.
    
    	Thanks for the replys,
    
    		Dan
    

    About the trim cylinders not being designed to hold up the unit for
    extended time periods: If that were true, how would an outdrive ever
    stay trimmed under load? There's mega-force on those rams when
    operating onder power, many times more than a static lifted weight.
    Let's be serious; those rams should hold that outdrive up for a long
    time, at least 2 months or more, with no travel. 
    
    Mike

RE: Note 649.7

>> -< Mis-information alert! >-

>>  About the trim cylinders not being designed to hold up the unit for
>>  extended time periods: If that were true, how would an outdrive ever
>>  stay trimmed under load? There's mega-force on those rams when
>>  operating onder power, many times more than a static lifted weight.

The info that I related was based on my experience with OMC outboards,
and I think I said that.  OMC I/O's may be different from the outboards.
But what you need to know is that the "trim" cylinders are *not* the 
same as the "tilt" cylinders.  OMC's outboard system uses a total of 3
separate cylinders for tilt and trim.  There is a single cylinder used 
for the tilt adjustment which is a coarse adjustment and moves the motor 
fairly quickly in the upper range if its travel.  There are two smaller 
trim cylinders which are only active in the lower region of motor travel,
and are a very fine adjustment, i.e. the travel is very slow.

So the bottom line is that the tilt cylinder could very easily be leaking 
or bleeding down and still allow the trim cylinders to function normally.
If the tilt cylinder bleeds down, the trim cylinders would only prevent
the motor from falling for about the last 10-20% of its downward travel.

>> Let's be serious; those rams should hold that outdrive up for a long
>> time, at least 2 months or more, with no travel. 
  
Agreed.  The dealer apparently also agrees and will fix it under warranty.
My original question still hasn't been answered though.  Does the Cobra
drive have a trailering lever that can be used to support the drive for 
long periods of time?  I'd be amazed if they rely strictly on the trim
system to support the drive while trailering.

Rick W.

    There should be some kind of support rod for trailoring, because of the
    stresses on the boat's transom. Maybe not the drive manufacturer, but
    certainly the hull manufacturer will make that point.
    
    Ray

    Rick, I know that there are several different systems in use for
    tilting/trimming, but this topic deals with OMC cobra, and that's what
    I'm talking about. There are two cylinders in this setup (just like a
    Mercruiser) and they do it all. there's no speed change in the range,
    either. It's all two equal rams, one on each side of the outdrive. 
    
    Why would you worry about the hull (transom) holding up this much
    weight during trailering? The transom in my 4 Winns is around two
    inches thich, and made of laminations of fiberglass and plywood. It had
    better damn well support that unit in towing/storage. I/Os are built
    very solidly in this area of the boat.
    
    Mike

RE: Note 649.10  

>>    Why would you worry about the hull (transom) holding up this much
>>    weight during trailering?

I'm not.  If I owned an I/O without a trailering support, my concern 
would be that a failure in the trim system (and they certainly *can* 
fail!) while trailering would cause the drive to drop to the ground.  
Your 2 inch thick transom may do just fine at supporting the weight of
the drive, but the aluminum skeg on your outdrive certainly isn't 
designed to be dragged on pavement at 60 mph!  

Rick W.

                      -< I gotta gadget fer that problem >-

re            <<< Note 649.11 by FAIRWY::WILSON "Moe, Larry, Cheese!" >>>

> I'm not.  If I owned an I/O without a trailering support, my concern 
> would be that a failure in the trim system (and they certainly *can* 
> fail!) while trailering would cause the drive to drop to the ground.  
> Your 2 inch thick transom may do just fine at supporting the weight of
> the drive, but the aluminum skeg on your outdrive certainly isn't 
> designed to be dragged on pavement at 60 mph!  

	Right.  That's what them thar little red plastic half tubes
are for;  to fit over the extended cylinder rods while trailering  IN
CASE a check valve, seal or whatever fails while trailering.

	Ahhh, the joys of trailering an I/O - I remember as if it was
only last year (-:, (-: 

	Reg

    What about a Mercruiser?  How would one check for air and/or bleed the
    hydraulic system?
    
    Thanks
    Herb

re                       <<< Note 649.14 by USCTR2::HWYDOM >>>

>    What about a Mercruiser?  How would one check for air and/or bleed the
>    hydraulic system?

	from memory......

	I think you just make sure the reservoir (usually WELL hidden) 
is topped up, then take it through the full cycle of trailer tilt 
position to full trim 3 or 4 times and check the reservoir again.
If there are bubbles on top you just bled (sp ?, past tense of the
verb to bleed, whatever) them out, if not you didn't need to and just
wasted some time.  Usual warning about making sure there's enough space 
to raise and lower the unit, etc., don't bring it down on someone's 
foot.

	R