Trim pump works, but may be on its last leg...

[rmurray]

'87 Merc 260hp with Oildyne Trim Pump/plastic reservoir "SAE J1171 Marine"

Haven't used the boat much in last two years, but on one of those trips, the outdrive would not go down. The trim motor was running, but nothing happened. I bled the system and topped off the fluid, and it seemed to fix the problem. Since then, it has been working, however, it does sound a bit rough going down. Going up, the motor sounds smooth and clean. Going down, there is a lower pitched whine that doesn't sound as healthy. I had some engine work done recently and the marine mechanic was a little concerned about the sound of it. With my "to do" list getting longer and longer, I don't have a lot of time to investigate, so I am wondering if it would be easier to simply replace the pump with a healthier used one (I can pick one up for $150), or is there a few simple things I can do before going that route? I can try cleaning the terminals, draining and refilling all the fluid in the system, but I'm not sure that will improve things. Any feedback is much appreciated. Maybe someone has a similar experience and knows how to give the pump a little tune up. Is it possible that the "down" solenoid is about to fail? Thanks!!

 

[Bondo]

Re: Trim pump works, but may be on its last leg...

'87 Merc 260hp with Oildyne Trim Pump/plastic reservoir "SAE J1171 Marine"

Haven't used the boat much in last two years, but on one of those trips, the outdrive would not go down. The trim motor was running, but nothing happened. I bled the system and topped off the fluid, and it seemed to fix the problem. Since then, it has been working, however, it does sound a bit rough going down. Going up, the motor sounds smooth and clean. Going down, there is a lower pitched whine that doesn't sound as healthy. I had some engine work done recently and the marine mechanic was a little concerned about the sound of it. With my "to do" list getting longer and longer, I don't have a lot of time to investigate, so I am wondering if it would be easier to simply replace the pump with a healthier used one (I can pick one up for $150), or is there a few simple things I can do before going that route? I can try cleaning the terminals, draining and refilling all the fluid in the system, but I'm not sure that will improve things. Any feedback is much appreciated. Maybe someone has a similar experience and knows how to give the pump a little tune up. Is it possible that the "down" solenoid is about to fail? Thanks!!

Ayuh,... The Down stroke is the low pressure side of the pump,...

My guess is yer Problem is corrosion bindin' the rams, at the caps...

 

[rmurray]

Re: Trim pump works, but may be on its last leg...

Thanks Bondo. That would explain the drive getting stuck in the up position. I read up on the rebuild, which looks fairly straightforward. Since this is the low pressure side, would this cause the pump to run rough? Lately, the drive has been going up and down no problem, just the pump sounds somewhat tired going down, which seems odd. In the event that I do want to replace it, is it best to just replace the electric motor, or replace the entire assembly, solenoids and all? Thanks again.