3.4L Merc Outboard Won't Stay Trimmed up...Drops Slowly-Need Advice

I'm looking for a little help/advice with the trim/tilt unit on my '86 Merc 3.4L outboard. While sitting on the trailer or while tied up to the dock the motor slowly drops down from the up position...and it's really starting to get annoying. From all the way up it will drop all the way down within about 45 minutes. I've been on here reading about manual release valves on various motors and am wondering if there's one on my big brute, and if so, where it's located. I guess I should start by checking if that's tight, then moving onto the fluid level and o-rings. I should mention that the cylinder is bone dry on the outside and not showing any signs of oil having leaked out. Any input you might have would be very much appreciated. Thanks.

Re: 3.4L Merc Outboard Won't Stay Trimmed up...Drops Slowly-Need Advice

OK, I'm a total newbie at boats & boating (see *NEWBIE* Disaster first day!) but I am just fixing a similar problem (one of many!).

After my overheating story and fire etc etc, I have been finding that one thing had led to another. My outboard also started to slowly drop. I filled the pump with oil, it seemed to be fine, but when I went back out, an hour later, I noticed it had dropped again.

Anyway, I found that my hydraulic hoses between the pump and outboard had been damaged during the overheating/fire. They had basically fused to the exhaust. I am in the processes of replacing the hoses right now.

You may have damaged hoses, couplings, crimps. Check both inside the motor/pump area and outside near to the manifold that houses the hose connections (under the outboard). Maybe the pump oil is leaking out from the pump? I did have pump oil in the bilge and so that was a bit of a giveaway.

Again, I'm no expert, but I am getting better! Another idea is to use the search facility, as I have many times, and search for trim hoses etc.

Andy.