I have a Mercury 800 80 HP 1973 with single solenoid trim and tilt pump motor. The motor burned out and I have located a after market replacement kit for the oil reservoir and pump unit made by ARC Marine, my question is has anyone performed this repair and if so what the out come was? It appears to be easy straight forward swap out.
I called ARC Marine and spoke to the motor technician...he said this is the replacement part for 1984 and older Mercury outboard Lift and Tilt systems...they used the same unit for years..he confirmed it's straight forward repair unbolt the reservoir and pump motor from the pump base replace the seal re-bolt the new reservoir pump base and the fill with oil; attached the wiring as removed and it's repaired. When I finish working on the interior of the boat I will be tackling this with the rest of the mechanical issues.
Lift and tilt pump motor...to repair it remove the electrical connectors and wires noting the positions and color connections then unbolt the oil reservoir from the pump and replace the seal and bolt the new unit on and replace the wiring in the same configuration as removed...I am going to rebuild mine in few weeks after I finish the interior of the boat....a 17 Ft MFG Gypsy I got for nothing that is in good shape...
The after-market parts work very well, and are easy to install on this style of power trim.
Make sure and properly place the short drive coupler between the pump in the manifold and the pump motor.
You need to bleed both up and down sides, there is a bleed screw for each side of the piston, that is on the top the one you see, and the bottom, near hose connection, to do this, both trim cyls need to be done. An air bubble can easily be trapped in the hose and just go back and forth never getting back to the resivoir to escape. It's a messy operation with lots of oil pumping out till it runs bubble free, you'll need a quart or two of 10W 30 which is what Merc recommends...Not hydraulic fluid. There is a detailed procedure as to how to do this correctly in Merc manuals, I'm not smart enough to post a copy of it here.
It's also important to do both sides and both cyliders so each is doing the same work to tilt the motor when under thrust load at speed.
I always do the procedure but of course people smarter than me have probably got a simpler method but, I doubt just cycling a closed system would work.
I just got done bleeding the system on my 1150 restoration.