Trim goes up, won't come down! Merc 140

swihartart

Petty Officer 3rd Class
Joined
May 4, 2009
Messages
82
1977 Starcraft 140 HP with Merc Outdrive / Prestolite pump.

Hello All,
I've driven my new old boat twice and have been fixing it for 2 months!
After hitting my first sandbar (see previous post about replacing trim cylinders) I've scoured these boards and read alot of great information from the members on how to ease my pain of having some unexplainable urge to be out on the water.​

After reading the merc #2 manual I downloaded (twice) I determined I should replace these things:​

- Lower end of a Prestolite pump (1 o-ring popped and it was leaking out of the "dog bone" bottom manifold. Filled with regular 10w-30​

- Hoses that go to distribution block (Black one on bottom of pump goes to fore side of block) Grey (from reverse to aft side of block).​

- Replaced distr. block. (used the markings to determine fore and aft).​

- Bought 2 trim cylinders (45520) on Ebay from Mercruiser Mike. (came in good shape, thanks Mike.)​

- Stainless steel hoses from block to cylinders (fore end of block connection goes to fore end of cylinder connection on both sides not sure if this is correct)​

- Bushings on trim cylinders (Do these need lube and how do I know if I've tightened the nuts and anchor pins that go through the rams correctly?)

After installing the above, I filled reservoir to bottom of threads with 10w-30, leg was all of the way down (in), made sure vent screw was backed out 2 turns. At this time I left the hoses from block to cylinder hang and worked the trim switch up and down for a few seconds, went back and saw oil dripping from a hose on each side. I checked the fluid level, topped off and connected the hoses to the cylinders.​

I ran the trim up for a few seconds and checked it, they're coming up!! Good to go. So I ran it all the way up. Now trim down it goes down almost all the way but stops. So I cracked what I believe to be the down side hose (aft on the cylinder and block on both sides) and the drive starts to drop slowly and I hear some air coming out, then fluid.
I retighten, check fluid, top off, run up no problem (pump seems to be working hard but it goes up) now down goes half way, stops. Repeat process of crack lines, listen for air, a little bit more but not bad, then fluid.
After retighten, run up no problem again, down consistently goes a little but stops. :confused:

I was also noticing that the fluid I would see in the clear tube before changing parts (also before stupid sandbar :mad: ) that goes to the reverse switch is now gone ie. there is nothing going through it anymore. I also notice that the oil that bleeds out of the lines when I crack them is really frothy, or air infused. Could this be the problem?​

Any advice is greatly appreciated, sorry for the long post but I thought the more info the better.​
 
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