Prestolite Trim Pump just installed and now won't go up

[JMSports]

Bought a Prestolite pump from Ship Shape Marine for a boat i recently purchased. The boat is a 1978 cee bee avenger 165 and it has a 1980 mercury 90hp inline 6 engine with power trim. I freed up the dual pistons...replaced the lines with a used set from ebay and hooked everything up. Filled the pump with fluid and worked the up button [trailer button because it seems the trim up is inop] untill it started to work. Got the engine trimmed up fully and partly down where it would hang up...finally bled all the air out and got the engine going full up and full down. On the last successful time i got the engine all the way down and hit the up and the pump runs but the engine won't move. If i open the knob (clockwise) i can manually lift and lower the engine with no issue but the pump seems like it's not flowing any fluid. I verified the resevoir is full and the vent is open 2 turns. There are no leaks on the system and i can actuate it down and that seems like its still working but it will not raise.

Any ideas? Maybe an oring blew in the valve body assembly but i have no leaks on the pump or lines. The pump sounds fine when it runs but it doesnt sound like its pushing any fluid like it was.

 

[JMSports]

No Title

 

[Chris1956]

I guess I would recommend you open the up bleed screw on the trim cylinders and see if you get good PTT fluid stream when you run the motor in the up direction. If no fluid, maybe the pump motor armature striped the pump body? It's a guess.

 

[JMSports]

I guess I would recommend you open the up bleed screw on the trim cylinders and see if you get good PTT fluid stream when you run the motor in the up direction. If no fluid, maybe the pump motor armature striped the pump body? It's a guess.

Ill be sure to try that once i get home from work...the pump does work in the down position still so its seems as if its bypassing and not pumping any fluid into the pistons.

 

[Chris1956]

If it pumps in the down direction, obviously the pump is not stripped. Make sure the manual bypass is tight. I believe it should be tight CCW.

Not sure if the manual bypass would cause the behavior you are seeing, but it is a simple fix. The next culprit in line, is the control valve. Those are non serviceable,and maybe hard to find a replacement at this time.