Noisy trim pump 90 HP Merc O/B

Georooney

Seaman
Joined
Sep 29, 2009
Messages
51
After a bumpy ride over a logging road, the trim pump has become quite noisy in the down direction. Up seems to be normal. I've drained and replaced the hydraulic fluid with Mercury trim fluid, and worked the motor up and down numerous times to get the air out. No joy. It still sounds like gears grinding, but only in the down direction.

Any ideas out there? My next step will be to remove the trip assembly and strip it down on the bench; just wanted to see if I was missing something that would make the job simpler.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,964
First of all what year is the engine. There has been more than one kind of power trim system.
 
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