Another Tilt/Trim Mystery

[Rayway]

I have a 1998 24’ f/g boat with a 5.7 GS Volvo Penta SX COBRA with only 80 hours on it and the leg dropped down by itself today while sitting in my driveway! How is that possible when I checked the complete system and everything is dry, there are no leaks and all fluids are full and there is no sign of the reservoir bleeding?? I even double checked every connection.It was fully up (the leg) this morning as it has been for the last 4 days since I’ve had it out last and when I got home from work this afternoon it was completely down on the concrete. I can’t tell if it dropped all of a sudden or slowly but I’m sure glad the kids were not around it as the usually are and what would have happened if I was towing it down the highway! Has anyone heard of this happening before?<br />Ray

 

[flashback]

Re: Another Tilt/Trim Mystery

sounds like the kid next door......

 

[Rayway]

Re: Another Tilt/Trim Mystery

Well the first thing I thought of was a prank too but the trim needs power and the battery switch is hidden under a bench seat where nobody knows where it is but a selected few plus the cover on the boat was all snapped down and did not look disturbed.<br />The older couple next door were out in front of their house which is right by the boat playing with their grand kids all morning and saw nothing so I'm stumped.Remember this is a fair size boat sitting in the open driveway in plain view and would take someone quite a while to accomplish the task if they did.

 

[Rayway]

Re: Another Tilt/Trim Mystery

Well it was right down again this morning.Someone must know how it could drop on its own?

 

[clanton]

Re: Another Tilt/Trim Mystery

Could be a leak somewhere, leaking check valves in pump, or fluid bypassing hyd cylinder piston.

 

[Rayway]

Re: Another Tilt/Trim Mystery

So I guess the only way to find out is to do some kind of pressure test? Do I just disconnect the wiring and the 2 hyd lines to remove the pump? I'm guessing it would have to go to a shop for testing?

 

[clanton]

Re: Another Tilt/Trim Mystery

I dont what t&t is on this engine, but most shop like to replace pump and motor to solve leak down problems. Check for manual release valve,may be loose. You have photo of pump and lines.

 

[Rayway]

Re: Another Tilt/Trim Mystery

I can't find any manual release anywhere on the thing and if I am supposed to store it in the down position then why does Volvo say to check the trim fluid ,pressure must be relieved by raising to the up position? I'm getting confused here?

 

[clanton]

Re: Another Tilt/Trim Mystery

I will try to find manual, It should have a double action cylinder, which means fluid on both sides of cylinder piston, and realy make no difference which position the drive is in for fluid check. I also dont think any hyd operated device should be stored with only hyd pressure holding it up.

 

[Rayway]

Re: Another Tilt/Trim Mystery

Thanks I would appreciate that.Can someone who really knows please CONFIRM if my Volvo Penta manual is wrong??I'm getting the conflicting advice on these forums. I quote the manual: "The trim/tilt hydraulics are pressurized WHEN THE DRIVE UNIT IS IN THE DOWN POSITION.The drive unit must be tilted to the full UP position to releive the hydraulic pressure before removing the level/fill plug.Failure to tilt the drive unit to the full up position before removing the level/fill plug would result in hydraulic oil being sprayed. With the drive unit tilted full up remove the level/fill plug the fluid level should be be at the bottom of the fill hole when the drive unit is at full tilt

 

[Good Ship Wood]

Re: Another Tilt/Trim Mystery

I know this is an old topic but my advise would be to find out where your check vaulves are. In the pump or is the cyliders. If the check vaulve isn't working properly the fluid can pass and cause the drives to drop. A quick way to determine where the problem is would be to take both lines off the pump and connect them together and see if the drives still go down. You will have to lift the drive and prop it up before disconnecting the lines. Once the lines are connected together remove the blocks and see if the drive drops. If it does than your lift cylynders are leaking internally. Good Luck...

 

[f_inscreenname]

Re: Another Tilt/Trim Mystery

First; Yes the outdrive has to be up before you open up the filler. You have to understand it takes fluid to push the trim cylinders out. When you draw the cylinder in (lowering the outdrive) the fluid is drawn out of the cylinders into the pump making its fluid reservoir under pressure. Put the outdrive all the way up, fill to proper level,reinstall screw tight but not to tight (alum is a soft metal).<br /> If there is no leaks then the fluid is flowing through the check valve when it shouldn't be (question being where it is,cylinders or pump?). I would call a dealer (at a time there are slow,my favorite 10:30am) and ask them where its at. Then get online and find your parts. Buying through a Volvo dealer is only a last resort. Changing a pump or cylinders is a piece of cake. <br /> Some people here will rebuild there pumps. I have never had any luck with that. Rather get a new/used one that works.