I've replaced the tilt/trim pump, hoses and bled the system. Drive goes up/down OK on land (after a little help), but now that I've re-launched, drive only goes up. It will go down with assistance (me standing on it while someone press the down button). Is there anything that I've over-looked? Is it time for new cylinders? Could a bad dash switchpad or limit switch have anything to do with this problem?

Thanks in advance,

D. Ocean
Pompano Beach, FLA

So the pump runs, but the drive does not drop? Have you done any work to the boat recently? Could be a pump issue, or it could be bad rams. Just because the pump is running does not mean that the valving inside is ok. You can do a preasure check on them. Does up go at normal speed but down will not?

Jon

Yes, pump runs and sounds "normal" in both directions, but drive will not drop unless I'm standing on it. Pump is less than a few hours old. After I get the drive to drop the first time, it will go up and down OK. However, if I raise it and leave it in the raised position for any length of time, I have to assist again to get it to drop. The drive always raises properly and at a good rate. I've tried swapping the hoses to see if I could "reverse" the problem, but it will still only raise and not lower.

How to test pump pressure?

Changing out the pump would be easy as I can do that while the boat is in the water. Changing the rams would be a pain as I'd have to pay to have the boat hauled, so I'm trying to narrow the issue down.

D. Ocean
Pompano Beach, FLA

They make a guage to test the pump. You can pull the pump and bring it to a dealer and they should have it. If I was at the shop I could take a picture of mine. However it does sound like you may have had a seal go in the ram, or they are binding up near the scraper.

Jon

I'll pull the pump and have it bench-tested. If it passes, all that's left is the rams.

Thanks again,

D. Ocean
Pompano Beach, FLA

Its more than likely the rams, there is a seal in the end cap that collects salt water, try replacing the end caps. You can get the endcap, and seal kit from BAM.

Yep. BAM is my first stop.

D. Ocean
Pompano Beach, FLA

Anyone in Broward/Palm Beach got a lift you ain't using for a few days?

D. Ocean
Pompano Beach, FLA

I'm no authority on the trim systems (yet) by any means. Perhaps I will be when I get my 1979 377 Scarab back together again. (staggered/trs/bw72C)

I do remember reading about this though. Perhaps you bought the newer high volume low pressure (HV/LP) trim pumps and are using them with the old style rams.

In TRS manual #5, Mercruiser claims that the "valving" is different between the old (internal line) and the newer (external line) rams. As such, using old style rams with newer pumps and vice versa is NOT recommended. I'm sure I too will be dealing with this issue but I have 8 Rams to play with. (4 of the old and 4 of the newer rams) BTW, I definitely have the old style presolite HP/LV pumps so please, let me know how it goes.

"Gotchya Covered"

Floched check unit in one of the lift cylinders. The Merc. test with the pressure gauges tells you which one. No other good shortcut. Trial and error?---You could get lucky or spend lots more $ than necessary before you get home. Get a copy of the Merc. shop service manual and be a Merc. mechanic. --- Jer