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  Raised outboard at rest - OK to dip in the water?

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Author Topic:   Raised outboard at rest - OK to dip in the water?
bwo posted 04-27-2003 08:49 PM ET (US)   Profile for bwo   Send Email to bwo  
When at slip, with Yamaha engine tilted all the way up, the outboard is totally out of the water. When I lower the fully raised engine just a few inches so its sits on its pegs when at rest, the bottom 3-4 inches of the skeg sits in the water. Does it matter if some of skeg sits in the water?
Sal DiMercurio posted 04-27-2003 09:26 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Most engine sit to low which in the lock position.
Don't allow the skeg to be in the water because you will get pitting or electrolosis even with good zincs.
Just tilt it as far as she goes & leave it "OUT" of the water.
I'v done that with all my engines & no problems.
Sal
brisboats posted 04-27-2003 10:27 PM ET (US)     Profile for brisboats  Send Email to brisboats     
You might want to try a 2x4 or similar wedged in to allow the motor to rest on a stop, keeps the motor out of the water and the constant pressure off the trim cylinders.

Brian

T Party posted 04-28-2003 03:35 PM ET (US)     Profile for T Party    
Is constant pressure on the cylinders a problem or will it cause a problem?

I have a brand new Johnson motor and I want to take good care of it. I noticed that Bombardier puts a little plastic part that they say is there to support the engine on a mooring. If I use it, a tiny part of the lower unit is in contact with the water, so I've been leaving it trimmed all the way up and not resting on that piece. Is this a problem?

Cpt Quint posted 04-30-2003 10:30 AM ET (US)     Profile for Cpt Quint  Send Email to Cpt Quint     
Fresh water or salt? Whats important here is to keep the exhuast intake out of the water especially in fresh water lake enviroment. this keep the "lake scum" build up out of your intakes. So too it would keep salt out of your intakes. In fresh water, as long as the skeg is painted you will develop a scum that can be sponged off and salt water should not be a problem. Im in a lake and I get the scum on the sked and bi-annually clean this but really as long as its not getting in the internal lower exhaust your not going to do any damage. Also whether you use you lock or tilt above to clear completely its not too much pressure on the transom. the lock is for pressure caused by trailer travel like a transom saver. but in the water,the water itself is a perfect spring cushon and the motor weight under wakes for exapmple is only disbursed into the water and not really placing any additional pressure anywhere.
brisboats posted 04-30-2003 05:27 PM ET (US)     Profile for brisboats  Send Email to brisboats     
I may be wrong but I always felt that if you took the pressure off the trim rams the seals would last longer. If the motor is extended all the way in the up postion and is not resting on a stop. It seems that the bouncing of a wake would exert greater pressure on the rams seals than if the motor were resting on a stop.

Brian

jimh posted 04-30-2003 08:00 PM ET (US)     Profile for jimh  Send Email to jimh     
In support of Brian's theory (that trailering with the engine on a mechanical stop instead of a hydraulic one is better), I have this anecdote.

I never had any trim or tilt problems with my engines, and I typically trailered them in the up position using the mechanical stop to hold them.

One trip I trailered about 800 miles with the engines tilted up slightly, resting on the dual trim tab cylinders (not the single tilt cylinder). After that drive the port engine began to show some leaking and would slowly lose its position. A bad seal? A coincidence?

jimh posted 04-30-2003 08:08 PM ET (US)     Profile for jimh  Send Email to jimh     
When leaving the boat in the water with the engine tilted up, be sure there is some zinc sacrificial electrode in the water, somewhere.

Usually extra zincs are mounted on the transom bracket of the engine, and sometimes there are cap nuts of zinc on the mounting boats, too.

If there are no zincs in the water that are in contact with your engine, the alumimum skeg becomes a prime candidate for galvanic corrosion from stray currents, etc.

bwo posted 04-30-2003 08:44 PM ET (US)     Profile for bwo  Send Email to bwo     
My engine is in salt water at a marina. Based on great advice received here, I'll raise the engine fully and make an improvised shim for support so that no part of engine will sit in water and no pressure will be exerted on cylinder/seals when at slip. Thanks again.
Chap posted 05-01-2003 09:27 AM ET (US)     Profile for Chap  Send Email to Chap     
Hello,
After engaging the stop, I also continue to cycle the rams all the way into their housings to prevent damage and funk build up.
Thanks
Chap
T Party posted 05-01-2003 12:14 PM ET (US)     Profile for T Party    
Chap-
I don't know what brand you ahve, but the new Johnson/Evinrudes don't allow you to cycle the rams back into their housings - I did that with my old Johnson, though.

It's one thing to put the trailering support in place, but for mooring I doubt that wave action in a protected river area will cause a seal to wear out sooner if I leave the engine all the way up (and not resting on the cheap plastic mooring stop which I don't think supports the weight anyway).

Salmon Tub posted 05-01-2003 06:15 PM ET (US)     Profile for Salmon Tub  Send Email to Salmon Tub     
If I may play sceptic here for a minute, how exactly does one know when the pressure is relieved from the trim/tilt cylinder? If a shim or piece of lumber or even the mechanical stop is used, then, consider the following: Before engageing, the cylinder is supporting the full (leveraged) weight of the outboard. When fully up, the outboard is almost completely balanced on the transom mount. As you lower it, the weight the cylinder bears increases. If you use something as a prop, then what will happen? As your outboard comes into contact with this prop, it will lodge, then if you overshoot just a bit, you will have actually applied a reverse force on the cylinder, accomlishing little. You will need to move it minutely up and down, and at best, guess when you find a point of equilibrium, especially if your boat is berthed and you can not stand behind the outboard and feel for play.

Jim, regarding your incident, consider the following, even though the cylinder is designed for in and out movement, you may have subjected the outboard to a bit of side play from turns, potholes, what not. The side play may have damaged a seal in your cylinder. Remember, the ram is made to move in and out of the cylinder, it may not be able to take too much side pressure, or at least not the seals.

brisboats posted 05-01-2003 10:04 PM ET (US)     Profile for brisboats  Send Email to brisboats     
Unfortunately I am not a mechanical engineer so my experience with hydraulic cylinders is limited to things that I have owned. But having a dairy farm in the family I was always taught to take the load off the cylinders when a piece of machinery was at rest. I am not arguing that my way is absolutely correct it is just the way I have been doing it and I have had great luck with my hydraulic cylinders. In my opinion when lowering the motor onto a stop there is no need to find the ultimate point of equilibrium the point is to take the static load off the cylinders. I have not seen an outboard manufacturer bulletin on this matter but my snowplow pump manual says to always lower the plow to a unloaded state when the vehicle is at rest. Works for me .

Brian

jimh posted 05-01-2003 11:15 PM ET (US)     Profile for jimh  Send Email to jimh     
When the engine is not running, the load on the cylinders is from gravity.

When the engine is running the cylinders have to resist the thrust of the engine's horsepower, in this case 70-HP.

I would think that 70-HP pushing the boat through the resistance of the cylinder would create a greater load than the gravity of the engine when at rest and not running.

where2 posted 05-02-2003 01:07 PM ET (US)     Profile for where2  Send Email to where2     
I vote we give JimH the honorary engineering degree. My 70Hp Johnson's resting lever fell off long ago. So, there she sits, partially raised in the tilt area (beyond trim cylinders), all the while she sits on the dock (yes on the dock). IMHO, If the tilt cylinder can bear the force of thrust beyond the range of tilt with the throttle at 3/4, then the force of gravity pulling on the thing resting at the dock is basicly inconsequential.

If you have equipment with hydraulics, and you leave the force on them, it tends to apply unnecessary force to the flexible lines, and in the event of a breakage while you are not attending that piece of equipment, it may drop and damage something below it. Ironically, the hydraulic unit of a power trim/tilt on an outboard typically does not have rubber lines, but uses a coiled metal tube to allow flexibility.

I side with JimH and find it difficult to believe that I'm more likely to blow a seal at rest, than if I am running 3/4 throttle and trim up beyond the trim range...

PMUCCIOLO posted 05-02-2003 11:35 PM ET (US)     Profile for PMUCCIOLO    
bwo,

Having been similarly situated about five years ago, I called the outboard manufacturer directly. The answer I received was to keep the engine tilted as high as possible to allow the lower unit to clear the water.

Once tilted, the hydraulic rams, seals, and engine bracket should be sprayed with a thin film of silicone spray weekly. They also suggested spraying from the gasket for the cowling down the the lower unit with the same type of spray to protect the finish.

Having the boat in the broiling Florida sun during four months of those dreaded fires we had, I can attest to the fact that their suggestions worked beautifully.

PM

Bigshot posted 05-09-2003 04:11 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
To save some wear and tear(if there is any) I tilt all the way up and then a QUICK bip down to relieve the prssure. Never had a problem yet, same for outdrives. If you use a jack plate it will clear the water by about a foot and then using the trailer lock works.

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