1984 90 hp Mercury trim/tilt problem

[Joe Kay]

I'm re-installing my trim & tilt pump and motor after repairs, and want to flush out the old hydraulic fluid first. I removed the fill plug and the allen plug under the reservoir but the fluid only dripped a bit and stopped. I figured there might be some debris blocking the drain so I pushed a pipe cleaner up the drain hole. That didn't do anything so I tried to open it up using an air compressor. It still didn't empty.
Is it possible that the trim rams need to be extended ir order to drain the fluid? They are not extended because I had to raise the motor manually to get at the reservoir.
Any help or comments would be appreciated.

Joe

 

[jimmbo]

http://162.144.28.33/lib/mercury/manuals/mercury_1965-1989_40-115.html#/354

 

[Joe Kay]

Thanks for the reply, but that manual seems to have the same content as my Seloc manual which I which I consulted before I posted. Relieving the pressure and removing the drain screw didn't work. There is another reason why the fluid didn' drain.

 

[jimmbo]

Well, perhaps the system is low on fluid. You might have to fill it up, cycle it to bleed the air, then drain it.

I don't have my service manual(factory) for my 84 115 anymore, and the ones online show a slightly different system in regards to fill hole and reservoir

 

[Joe Kay]

I was trying to drain the hydraulic fluid before installing the pump and motor. I ended up filling the reservoir through the fill tube and sucking it out of the reservoir with a turkey baster. I did this several times before placing the pump into the reservoir.
Then I filled the system with automatic transmission fluid, hooked up the wires, and tried the trim/tilt. It made a whining noise but did not raise the outboard. I had replaced the seal in the top of the pump because it looked worn and replaced all the o-rings. I also had the motor rebuilt. I guess the pump has failed and I need to replace it. Any ideas where I may be able to get one? Mercury does not sell that pump anymore and the aftermarket pumps with the same Mercury part number are different and don't fit into the reservoir. My original pump has a flat bottom. The aftermarket ones being sold now have a bracket on the bottom and some other protrusions. You can see the difference in the diagram on page 9-39 of the online manual you referred to me. Part # 50.