Power Tilt No Go Down

[Racer57]

I have a 2007 3.0L Merc Alpha one I/O. At the beginning of the season I realized I was unable to lower the power tilt. I took it to a shop and he supposedly fixed it for about $90. He gave me some hooey about a hydraulic lock and not to keep it raised all the way or it might lock again. Anyway, it worked fine all summer until about 2 weeks ago.

The symptoms are that when the tilt is raised I can lower it about half way and then it stops. Just as it stops going down, the motor pitch changes to a kind of higher pitched squeal. When I cycle the tilt back up/down about 5 -10 times it then seems to work just fine. Used the boat for two days no issues.

The next weekend, same problem, tilt would not lower. Cycled up/down about 5 times, then all is well for the day.

This weekend ? repeat. However, even after cycling up/down, it still only goes down half way.

Fluid level is good, no physical damage to outdrive. Battery fully charged.

Any thoughts?

 

[Don S]

Re: Power Tilt No Go Down

He gave me some hooey about a hydraulic lock and not to keep it raised all the way or it might lock again.

It's not "hooey", it's a fact. The pressure relieve and check valves in the hydraulic pump can jam after being raised full up till the pump bogs down. Best to raise the drive and do a quick down click of the down button to kill the high pressure built up by the pump when full up.

IF the reservoir is full (take the cap off and look, don't go by what it looks like from the outside), then one of the valves is probably leaking internally.
Donwload section 1C of the OEM service manual here http://www.boatfix.com/merc/Servmanl/14/14notice.pdf

It's the troubleshooting section and tells you how to test things.

 

[Racer57]

Re: Power Tilt No Go Down

Although I was not confident in his answer, I have not left the tilt all the way up. In fact, this last week it was only half way up, now it won't go down past that point.

 

[Racer57]

Re: Power Tilt No Go Down

So I switched the down line with the up line at the trim pump. Motor went down OK, but now has difficulty going back up.

So it appears that the issue is not downstream of the tilt pump (rams, lines etc) but maybe something associated with the pump adapter - shuttle, pressure relief valve(s), poppet valve(s)?

Any better way to narrow that down? Or does it matter - pieces/parts can't be bought, must buy entire pump adapter?

 

[stonyloam]

Re: Power Tilt No Go Down

So I switched the down line with the up line at the trim pump. Motor went down OK, but now has difficulty going back up.

So it appears that the issue is not downstream of the tilt pump (rams, lines etc) but maybe something associated with the pump adapter - shuttle, pressure relief valve(s), poppet valve(s)?

Any better way to narrow that down? Or does it matter - pieces/parts can't be bought, must buy entire pump adapter?

I believe you are having trouble going up, because the down (now up) delivers a lot less pressure to the cylinders. Best to switch back and find out what is really wrong.

from the book:
Valve Pressure Specifications:

Up Circuit 2200-2600 psi
(15173-17932 kPa)
Down Circuit 400-600 P.S.l.
(2759-4138 kPa)

 

[Don S]

Re: Power Tilt No Go Down

Relief valves and repair kits are available from Merc, as far as testing follow the procedures in the OEM service manual.
Here is a link to the section on trim pumps. http://www.boatfix.com/merc/Servmanl/14/14a5.pdf

 

[Racer57]

Re: Power Tilt No Go Down

I did switch back, just wanted to narrow down the cause. Thanks for the link.

 

[jerryjerry05]

Re: Power Tilt No Go Down

AS you cycle it up and down spray some lube on the rams.It might help. Might not??? J