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79 Johnson 140 Tilt/Trim Problem

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shanenest

New member
We have 79 Johnson 140 outboard that will not stay trimmed up. I have tried refilling the fluid and bleeding it out by moving the motor up & down topping off the fluid multiple times. Sometimes the motor stays up for 12+hours but it always falls back down. From what i've read maybe it needs new seals?

Can the seals be replaced with the motor on the boat?
Can anyone point me towards a instructions? I have seen videos of other motors but cannot seem to find anything this old.

Thanks for looking!
 
That PTT unit is self bleeding.

Have the engine in a extreme up tilted position when refilling the reservoir...lower/raise to dsitribute the ffluid. Repeat the filling procedure as needed. I assume that you're aware that the reservoir fill screw/seal must be replaced before lowering the engine.

I also assume you're aware that the manual release valve needs to be released 2 turns (no more than 2 turns!) to manually lift/lower the engine... but... it needs to be tightened to test.

The usual cause of the problem you speak of is a lack of fluid, especially if it'll stay raised for 12 hours... BUT... there is also a common problem, a short rubber tipped valve located under the oil pump which is under the electric motor, a PITA job as the PTT unit must be removed in order to remove the electric motor. Let us know what you find.
 
Boobie... Frankly I forget what it was called other than it was a relief valve... sorta sets in my mind though as a Trim Down relief valve. During the early years of the single ram tilt, dual ram trim units, I lost track of how many of those things I had to replace due to the unit/engine slowly dropping.
 
I tried topping off the fluid again last night & the motor is still up this morning. I was not putting the fill screw back when moving the trim up and down to distribute the oil. Am I supposed to move the motor up and down manually with the manual relief screw open (no more than 2 turns) or can I move it using power, or maybe both manually and power?

Thanks so much for the help!
 
shanenest said:
It dropped about 1/2 inch overnight.
Click to expand...

You'd have a hellava job finding a leak as slow as that.

I assume you found out that if you did not replace the drain/fill screw that when you lowered the engine you lost the fluid out that hole as the engine lowered. The purpose of having that screw seal replaced is to force the just added fluid to flow where it's needed.

When you finally tilt the engine up to add more fluid and find that the fluid is already up to the edge of the hole, it's full and the presence of any air left is unlikely.
 
Yes, I could see that some fluid was draining but hard to tell how much as I was up at the front of the boat.

Do you think it might be leaking through the fill screw or the manual release screw? These is a small gasket there that looks very work out.

The problem is that after a few days the motor is sitting on the bottom of the lake. Some days it hardly drops at all, maybe an inch or half inch, other days it drops several inches. I will top off the fluid again.

Thanks.
 
If it leaks at the fill screw (has a "O" Ring seal) or the manual release valve (also has a "O" Ring seal), you would see fluid dripping from those areas.

Use the manual trailering lock of the engine to hold it up when having it in a tilt up position for a long length of time.
 
The motor stayed up for about a week on the trailer, but when I put it in the water yesterday it fell down all the way overnight on the dock.

I wish I could use the manual lock but the way the motor is mounted it doesn't go up enough to get the lock in place.
 
Unfortunately with a intermittent minor leak such as what your engine has in the PTT unit, you have three choices, none of which are ideal.

1 - Tear the unit completely down and replace all of the O Rings, test all the valves, in general... replace anything that might leak. In that torn down mode, you might just come across something that floating around that interferes and causes a leak once in a blue moon.

2 - Replace the entire unit with another good used unit that does not leak down.

3 - Live with it by using a 2x2 or a 2x4, laying down across the two transom mounts, a rope tied to each end and tied in front of the engine to keep it there. If the engine starts to fall, it will rest on that board in the tilted position. Remember to always raise the engine hydraulically before removing the board..... you do not want that engine falling all at once.
 
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