Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

Mercruiser power trim slow to rise


waynej's Avatar
Member

Join Date: Jan 2005
Posts: 8

05-02-05, 09:00 AM   #1  
Mercruiser power trim slow to rise

Hi,

I have an alpha 1 outdrive on a 140hp mercruiser. The stern is very slow coming up but normal going down. I bought the boat with this problem just recently (I'm in a restoration project) and this has me stumped.

The hydraulic motor works fine, but struggles and overworks when raising the outdrive. I bled the system entirely, and it worked normaly once, then the problem persisted. So I loosened the pressure lines on the rams (the ones that are responsible for down) and the stern rose perfectly - other than all the fluid flying around, of course. If I leave the line off just on the left ram but reconnect the right, everything works fine, but when reconnected, the stern goes up once normally and then the problem is back. Fluid flows freely from the "up" lines when I disconnected them and ran the trim up.

My best guess is is the left ram is buggered somehow. Can this be fixed or is this even the problem? Any help appreciated.


Cheers,

Waynej

 
Sponsored Links
ncmurf00's Avatar
Member

Join Date: Nov 2007
Posts: 13
SC

03-11-09, 05:40 AM   #2  
Any luck?

Wayne,
Did you ever find a resolution to this? I'm having the same problem with mine (75 Startcraft Islander w/Alpha 1).

One day, my trim rams blew all seals. Replaced the trim rams and the pump. Everything should be good just like your situation. Bled the lines I can't tell you how many times. Same end result though, the motor overheats trying to raise it up.

 
samuari's Avatar
Member

Join Date: Jul 2008
Posts: 541
MN

03-11-09, 08:08 PM   #3  
ncmurf00 was the outdrive free with the rams off? Are the rams the same lengh wen collapsed? Other than kinks in the hyd. lines I can't think of any other problems that would cause pump to overheat.

 
ncmurf00's Avatar
Member

Join Date: Nov 2007
Posts: 13
SC

03-12-09, 06:01 AM   #4  
Completely Agree

When the rams are off, they close at about the same pace/speed. When extending, there's a more noticeable difference, by about an inch or two. When you apply some backpressure to the one that extends faster, the other catches up.
Odd thing is that when I was replacing them, I found that 1 of the rams had the lines crossed (up/down). Created more pressure for 1 ram to carry the load. Ever since I corrected the cross, it seems like there's not enough pressure to pull up the outdrive. The pump runs longer which makes it hot, then overheat and cut out.

 
samuari's Avatar
Member

Join Date: Jul 2008
Posts: 541
MN

03-12-09, 07:39 PM   #5  
With the ramsm off the outdrive can you lift it? It should move free.
Did you just get the boat? I have never switched the hyd hoses but I would think it wouldn't work at all or blow the seals. If the system worked the way the hoses were that might be your problem.

 
ncmurf00's Avatar
Member

Join Date: Nov 2007
Posts: 13
SC

03-12-09, 07:49 PM   #6  
I actually got the boat back in September and got some use out of it for a while. The previous owner warned me about it losing oil, and to top it off before each trip.
Things started going downhill when the pump went out. (Was working fine prior to with the exception of going through oil like crazy.)
First thing was getting a new pump. During the bleed process, I found the crossed lines (when free, only 1 ram was moving freely). Followed the service manual which I was lucky to have, and straightened it out. After a few up and down tests, the seals blew out in both rams. Checked 3 times to make sure it was correct. Replaced both rams, and connected the lines correctly and they moved freely when disconnected. As soon as I put them back on the outdrive, it really works the pump to life the outdrive. I've even loosened the bushings, lubed the shaft, and still the same result. I have a suspicion that there's a slight obstruction in one of the lines. The up line is a single hose off the pump, then goes to a manifold of sorts to feed both rams. Although I replaced the lines to the rams already I wonder if the obstructon is in there. 1 ram might be getting the bulk of the pressure and is pulling both the outdrive and the 2nd ram that isn't getting good flow? Almost like it's fighting against itself.

 
waynej's Avatar
Member

Join Date: Jan 2005
Posts: 8

03-17-09, 06:52 PM   #7  
Hi,

I had dirt on the screen in the reservoir. It comes up much better than it used to, but still has symptoms of the same problem. Oddly, it works perfect about 20% of the time.

I'm going to check the lines back at the pumpt to see if they are crossed - I never thought of that - although it seems to be working OK now.

Wayne

 
ncmurf00's Avatar
Member

Join Date: Nov 2007
Posts: 13
SC

04-07-09, 06:32 AM   #8  
I don't know if this applies to your situation, but here's what I found.
On the models we have, there's a reverse lock on top of the engine where the throttle/shifter is tied into. It's also where the neutral cutoff switch is.
If you move the shifter (while engaged) back and forth, you'll see the cam moving as well. This cam hits a little switch, but the pivoting shaft itself also engages the reverse lock. What this does is if you're in reverse, it locks the oil lines so that the outdrive doesn't pull itself out of the water while the prop is pulling in reverse. If the adjustment is a little off, it might prevent fluid from allowing the outdrive from rising properly. Try moving the shifter into forward gear pretty far to see if the problem corrects itself. If it doesn't, then the valve is stuck/dirty and need to be cleaned out or the springs might need replacing.

Thanks,
Jeff

 
Softy's Avatar
Member

Join Date: Nov 2009
Posts: 2

11-08-09, 03:38 PM   #9  
Hello,
I'm having the opposite problem, my outdrive comes up freely but won't go down. I was going to replace the rams but I am not confident that will solve the problem.Any advice would be greatly appreciated.
Softy

 
ncmurf00's Avatar
Member

Join Date: Nov 2007
Posts: 13
SC

11-11-09, 06:43 PM   #10  
Good evening,
I've seen this happen on mine before... right before I replaced the rams and hydraulic lines.
Do you have any fluid leaking out? Sounds like air in the return lines.
Try bleeding the lines and see if there's any change.

Thanks,
Jeff

 
Softy's Avatar
Member

Join Date: Nov 2009
Posts: 2

11-12-09, 03:31 PM   #11  
My leg's a kicking now

Giday,
I got hold of a pair of second hand rams and fitted them, problem solved.The old rams are stuck fast at nearly full extension.
Thanks

 
Search this Thread