Trim Tab Motor Port side - No upward movement

[bigralph]

1990 F32
Last question today:
Port & Stbd trim tabs. Port side no motor sound in up direction. Checked the switch yesterday and I think that it is functioning properly. PO left the trim tab hydraulic reservoir plug out, my genset mechanic found it in the bilge. There is fluid, but it looks like it is below the line. I don't know what fluid to use, but don't think that would prevent me from hearing the motor stroke in the upper direction. A guy at a boat store local told me yesterday to check the ground continuity; that's not a bad idea, but that means I need to go buy a sufficient length of wire for a test lead. I've considered pulling the leads from the helm, pulling leads off trim tab motor, and installing a 9-volt battery at helm to check at motor. Still, all that will tell me is that I have a good cable. Assuming I do, then what's next? Any thoughts on motor sound in down stroke but not in up?

Thanks.

[larryeddington]

Check that you are getting command signals first at the pump, if not then wiring or switch if so then best bet is hydraulic solenoid valve which Boat leveler sells. I had to replace one.

[The Dog House]

Boat Leveler sells biodegradable fluid for the trim tabs. Most people I know use automatic transmission fluid (DEXRON III). The Boat Leveler manual says automatic transmission fluid is acceptable for use.