1977 1500 - Cannot Lower Motor

[Kargh]

Hello!

I hope someone can offer some advice. I've spent all morning trying to resolve this issue but so far, no luck. The motor is stuck in the up position and I cannot find any sort of manual relief valve on this 1976 or 1977 Mercury 1500. Is there one? If not, how would I go about manually lowering the motor?

Thanks!

 

[CV16]

If the power trim pump is in the boat, turn the big knob and you should be able to lower it. Is the little lock lever down that holds the motor up?

 

[Kargh]

Trim pump is in the boat. Turning the control valve doesn't let it lower. The motor is not locked in up position. End of last season, the day I was going to move the boat into storage, I went to lower the motor and had no power to it. Previous to that, the up/down controls had been acting up but the previous owner(s) redid all the wiring and it is rather awful, so I wasn't surprised that it lost power completely.

There must be a way to manually lower the motor though.

 

[Alumarine]

According to the manual that valve is for manually tilting up only.
It says to open the bleed screws on the bottom of both cylinders.
I'm sure if you disconnected the hoses it would come down as well.

You could apply power to the pump and see if it works.

 

[Chris1956]

If the motor is titlted up under power, the manual knob will not lower it, but you already knew that. Loosen one of the larger hydraulic hoses at the pump/reservoir to lower it. Alternatively, remove one of the bleed screws on top of the PTT cylinder. Oil will shoot out, and motor will lower. Refill the PTT pump/reservoir.

 

[Kargh]

I've tried loosening the bleed screw for both up and down on the cylinder, that didn't do anything. I have not tried loosening the bleed screws on both cylinders though, nor have I tried loosening / removing any lines. I was hoping to avoid removing the lines but it might be the only option I have left.

I will report back the results later this morning after I give both these options a try.

Thanks!

 

[Chris1956]

You need to remove the bleed screw to allow the oil to shoot out. I would think removing one would do the job.

 

[Kargh]

You need to remove the bleed screw to allow the oil to shoot out. I would think removing one would do the job.

Oh, it did. I was unprepared for the violent expulsion of oil though!

So, one other question.. according to the manual I have, circa 1976, in order to bleed the cylinders when refilling them, I need to remove the cylinder and flip it over in order to bleed the 'up' side. Is this true?

 

[Alumarine]

When I installed power trim on my old merc 50 I don't believe I did anything to bleed it.
I just cycled it up and down and it worked.

 

[Kargh]

When I installed power trim on my old merc 50 I don't believe I did anything to bleed it.
I just cycled it up and down and it worked.

Hmnm. I'll have to try that when it comes time.

I've seen references to using 5w-20, 10w-20, and ATF. Which is it? Will any one of them work just as well as the others?

 

[Alumarine]

I've used 10W-30 motor oil and ATF.
Should probably use what was in there then you won't have to flush it.

 

[Chris1956]

The manual is correct. If you need to bleed the cylinders, you will need to remove them from the PTT brackets and face the bleed screws up. to allow the air to bubble out. However, if you pull on the lower unit and it has no play, you do not need to bleed them.

Refill with 5W-30 or Dextron II ATF, whichever is already in there.

 

[Kargh]

Quite honestly, I have no idea what is in there.

 

[jimmbo]

The oil mercury said to use was SAE 20. The inverted ram procedure was for on installation where the rams are empty. When you 'bled' your system to lower the engine, you were releasing fluid, so topping up the reservoir should be all that is needed, unless you lifted the engine while the bleed screws were open

 

[Alumarine]

Quite honestly, I have no idea what is in there.

If it's red it's ATF.
If it looks like motor oil, it probably is.

They are the least fussy type of hydraulic system as they're rarely used.