mercury outboard trim tilt problem

[sparky4612]

I have a 1984 Mercury inline 6 with a integral? tilt and trim. There are 3 rams: one for the tilt and 2 for the trim. There is a trailer button and a trim toggle on the control box. When I trim up or press the trailer button the motor lifts slowly at first and then rapidly after the 2 trim rams are fully extended. The problem occurs when I press the trim toggle button to lower the motor. The motor moves down smoothly until it hits the extended trim rams. It sounds like the trim rams are not retracting properly and the tilt ram is forcing them down or pushing against them. They make alot of noise and sound like they're binding. I tried to bypass the selenoids but the same occured. Is this normal? If not, what's the problem?. Any help is appreciated. Thanks

 

[achris]

Re: mercury outboard trim tilt problem

Sparky,

Sounds reasonably normal to me, just check you have enough oil in the reservoir.

Chris.......

 

[ddrieck]

Re: mercury outboard trim tilt problem

Not sure if the Mercs work the same but on my 150hp Force when trimming down the it will go like crazy and then slow down as it gets to the point of the tilt trim angle sweep. Will go slow on the way up until it reaches the end of the trim angle sweep and then goes like crazy.

 

[Texasmark]

Re: mercury outboard trim tilt problem

That setup is 2 tilt cylinders and one trim. The lowest movement is with the trim cylinder engaged (slow moving but lots of power for trimming pressures) whereas when you get up to 20 degrees (Merc says 20 but they are divided fore and aft of the engine vertical position....don't know the exact numbers; anyway some distance up or out from vertical) the trim cylinder is bypassed and the tilt cylinders finish the job all the way to the top. The tilt speed is faster in the tilt only range because the volume of the trim cylinder is not in the loop. However, there is a pressure bypass on the tilt system and if you have trim above the trim angle max and go faster than idle-slow speed range, the bypass will open and the engine will will be driven down to the top of the trim range and stay there till you toggle the switch again.

I had an '84 with this arrangement, but that was years ago. Currently I have a manual covering 97 models "and up".

Your fill procedure shouldn't be that far from this: My current manual says(which should be the same as yours as there really was no reason to really change this part of the design) to raise the engine to the full up position.....trailer button probably does this.

Somewhere on the motor/pump gearbox that drives the hydraulic pump, probably close to the bottom of the pump part of the combo, should be a rather large (roughly 1" OD) threaded plastic cap. Remove the cap and check/fill the oil level. Full is even with the bottom of the fill hole (for a vertical plug and probably bottom of the threads for a horizontal one). "Fluid is Quicksilver Power Trim and Steering Fluid or regular automotive ATF." Cycle the system several times (slowly to give any bubbles time to dissipate, especially at up and down limits) after filling to force out any bubbles (little noise makers).

Noise to me would be cavitation caused by a low oil level in the reservoir as achris mentioned. I think you check it with the engine in the full up tilt. I will go out to the shop after while and look in my manual to tell you exactly with location of the fill screw, fluid to use and full level.

I looked in the troubleshooting section of my current manual and there were no recommendations on combating noise other than what I said about fluid.

Mark

 

[circlehook]

Re: mercury outboard trim tilt problem

yea mark every thing you said is right and in the up position is also where you can bleed the air out of the system, also that was in my repair manual, the problem I had was the seals blew out on mine and from the crorosion ate away the housing around the seals and I had to replace the whole unit. very ez job to swamp out units good luck bob

 

[sparky4612]

Re: mercury outboard trim tilt problem

Thanks for your all your helpful information. I should probably describe the noise better because I still don't think this is normal for my unit. After the motor drops to the trim rams it sounds like the tilt motor is still engaged and pushing against the trim rams as they retract. The motor sounds like it's working hard and the trim rams sounds like they are binding and slipping from the contact points on the back of the engine. There are 3-5 large knocking noises as they are retracting which leads me to believe the trim rams are are being forced down by the tilt ram. I checked the fluid and filled to the proper level as it was low. I raised and lowered the engine manually using the manual release and continued to top-off the fluid. In the process I broke the manual release plug off but in the closed position. I'll have to replace but not right now.

I've never owned a boat with a trim system like this and am worried I'm hurting the system (I can't afford a new trim system). It sounds like you all know what the problem is so if this changes your diagnosis let me know. Thanks again!

 

[Texasmark]

Re: mercury outboard trim tilt problem

Sparky, did you post this question in two places on the site. I feel like I responded to your last input just this morning. If you do have two, go to the other one..........naw. I just remmebered; I responded to your PM. Check your PM.

Mark

 

[freiguy]

Re: mercury outboard trim tilt problem

I'm having the exact same problem. Did you ever find a solution?

Thanks.

 

[RRitt]

Re: mercury outboard trim tilt problem

binding on downstroke is usually caused by wallowing of cylinder head or deformities in the strike plate (underneath side of swivel). If you let it go long enough it might tear up the big ball bearing things on end of trim pistons.

 

[freiguy]

Re: mercury outboard trim tilt problem

Thanks for the reply. Unfortunately I don't quite understand what you mean but I gather that it is a major repair that would need to be done by a professional?

 

[RRitt]

Re: mercury outboard trim tilt problem

Thanks for the reply. Unfortunately I don't quite understand what you mean but I gather that it is a major repair that would need to be done by a professional?

usually the longer you let it go on then the more major it becomes. At first it is just a simple matter of rebuilding the trim rams.