inconsistent power trim

vicrydr

Recruit
Joined
Dec 26, 2014
Messages
3
1986 mercury 175 Power trim sometimes trims up but not down. Sometimes trims down but not up. sometimes works both ways just fine.
Was coming in off the lake Saturday and had it trimmed down. It wouldn't trim up to put it on trailer. I turned around and put the boat on plane and it trimmed up just fine. Put it on the trailer and it won't trim down. What gives? Loose connection somewhere?
 

Bondo

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Apr 17, 2002
Messages
71,413
1986 mercury 175 Power trim sometimes trims up but not down. Sometimes trims down but not up. sometimes works both ways just fine.
Was coming in off the lake Saturday and had it trimmed down. It wouldn't trim up to put it on trailer. I turned around and put the boat on plane and it trimmed up just fine. Put it on the trailer and it won't trim down. What gives? Loose connection somewhere?

Ayuh,.... Most likely corroded wirin' terminal ends at the pump,...

Disassemble, clean, reinstall, 'n protect what ya did,.....
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,605
Any time you start having intermittent problems with anything and it has switches, and wires and pumps and such, it is almost always like Bondo stated, connections or a faulty switch. As far as finding where your pump is located, follow the hydraulic hose. You will find it.
 

vicrydr

Recruit
Joined
Dec 26, 2014
Messages
3
Yep. Got it. The pump is outside the boat on the motor clamp/mount. Two wires running into the top of it through a plate bolted on top. Being hesitant to tear into that I traced the wires back to two relays mounted on the side of the motor. One clicked when I tried to trim down, the other activated when I trimmed up. I switched them. Then I was able to trim down but not up (opposite) I got a new relay at auto zone (Duralast 19861) Works fine now. Thanks to all for the replies.
 
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