Tilt/Trim Hydraulic Pump Problems-Need Help

New Boater 1

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Sep 21, 2010
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I am 16 and I bought my first boat in June this last summer.
It is a 16' 1978 Avenger. I bought it for $400 and spent the whole summer rebuilding it. I redid all of the floors, hull foam, and fiberglassing all by myself. I also had to rebuild the engine which is a Black Max 1978, 150 Hp, v6, Mercury Outboard. I had to replace both switch boxes, the trigger, and stator. And rebuild the carburetors. I got it to run great! And I just got all the upholstery done last week.
Saying all this, Now i just cannot figure out the Tilt/trim. I have taken my boat out twice by putting a rope around the engine to keep it down while in reverse and manually lifting it to put it on the trailer. But, I really want to take it out this weekend with friends and my parents will not let me take it out by myself until the tilt/trim works correctly.

I took apart the original Hydraulic motor and found that it was bad and I had to buy a new one. So I went to the mercury shop and looked through his "boneyard" until I found the exact same motor that is on my boat. I tested it and it worked so I bought it. I then took it home hooked it up, and filled it with motor oil. I was told my model was self purging so I just kept pressing up then down, on and off for a while. I had to refill the reservoir several times. While I was doing this the motor did not move at all. I wanted to see if it would resist me lifting it manually and it did. It resisted lifting manually.
The motor does not go up or down at all when the hydraulic pump goes.
So I took off one of the hydraulic lines and watched the flow out of the pump while I pressed the button, the oil just kind of oozed out. But the motor runs stong.

How can I get the Hydraulic pump to move the motor up and down?

After a whole summer of work and lots of money put into this boat it is very annoying having this hold me up. I just want to get on the water this weekend.

I have also been having issues with one of the solenoids, is there a generic solenoid I can buy at an auto parts store?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,559
Re: Tilt/Trim Hydraulic Pump Problems-Need Help

That motor has the pump unit in the boat, right? There are two motor/resevoir units that look identical, however, the armature on one of them is too short to mate with the oumo unit on the other. I think you need the motor with the armature that is flush with the bottom of the resevoir.

Those PTT units are not self bleeding. You have to bleed each cylinder seperately. On the top of the cylinder, next to the grease fitting is the down bleed screw. Remove it and run the motor in the down direction. When pure oil comes out (5W-30 motor oil is recommended for the trim), w/o any air bubbles, install the bleed screw and bleed the other cylinder the same way. Now to bleed the up side of the cylinders, you need to unbolt them from the motor. Next to where the hydraulic lines connect is the up bleed screw. Face it up and remove it. Run the motor in the up direction until you get pure oil, replace the screw and bleed the other cylinder.

A note on that Avenger. I have the '74 16 footer. It is rated for 85HP, but came with a 150 inline six. Takeoff speed is 50MPH. If you hit a wake at that speed, you will leave the water.

Hold her real steady after you pass 5KRPM, or it mght flip..... Watch the transom for cracks, as that V motor will really put some stress on her.
 

New Boater 1

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Joined
Sep 21, 2010
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Re: Tilt/Trim Hydraulic Pump Problems-Need Help

Thanks a lot. I got a new pump part, not the motor, and bled it and now it works!
Turns out my pump was bad.
 
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