Trim Question - Motor Runs - but no tilt/trim

[Woodbinekeith]

Have a 1990 Merc 3 Cyl. 90 h.p. with Commander 2000 control that is new to me and I'm just learning. I have the thick service manual.

Hydraulic fluid is right up, and motor is up and braced in "trailer" position. Using the "up" and "down" before manually lifting it up resulted in the motor humming nicely but there is no lift in either the tilt or the trim.

There are four electrical connectors in a group just inside the cowling that come from the control. Two I have hooked to matching blue/white and green and white from the engine but the other two are not connected (doesn't seem to be anything handy to plug them into). It seems the brown/white is supposed to go to the trim sender and the tan one I don't know where it is supposed to go.

In reading the manual, I'm looking at the brown/white line that is supposed to go to the "trim sender. Since the brown/white line is not connected - what will be the result? Perhaps this is my problem. What exactly does the "trim sender" do when it is hooked properly. Better yet, what happens if the trim sender is not connected. Thanks in advance

 

[RRitt]

Re: Trim Question - Motor Runs - but no tilt/trim

if it is a recently new motor then you somebody may have forgotten to check the hex drive shaft. The length needed changes from motor to motor. A new motor usually has a bag of a few different lengths and you have to pick the right shaft. If you don't have the right shaft then motor does not engage the pump gears.

If you have the right shaft and the motor is spinning ... and the fluid is topped off .... but the system doesn't lift ... then you need a hydraulic rebuild.

 

[Chris1956]

Re: Trim Question - Motor Runs - but no tilt/trim

trim sender sends aprox trim of motor to the trim gauge. It has no bearing on your issue. Tan wire is usually overheat sensor. Some mercs had overheat buzzer sender and temp gauge sender. Again no bearing on your issue.

Following what RRIT said, does the PTT motor look new? if not, you probably have massive amounts of air in PTT system. Run the PTT system down, and lower the leg manually. Now run PTT up and raise it up and see if you can add fluid, if so, you are on right track. Repeat process.

if not, you need to pull PTT unit off and have it checked out.

 

[aussieflash]

Re: Trim Question - Motor Runs - but no tilt/trim

Check for leaks from rams or hoses.Definitely sounds like air in system.As Chris said (up down fill up down fill).Keep checking till it takes no more fluid.

 

[Woodbinekeith]

Re: Trim Question - Motor Runs - but no tilt/trim

I'm not seeing any leaks from hoses/rams and have cycled the motor many times by hand. I replaced the three 0 rings on the manual release valve and the 0 ring on the hydraulic fill plug. No change. With the release valve full clockwise - the motor still falls (controlled by hand - not even a slow leak) from the full trailer tilt position down to about 5" from the bottom where the two trim pins do hold it from going the last 5". Pressing "down" at the control switch will take the motor down the last 5" but there is no lift with the "up" switch, even though the motor is working. Pressing down on the motor does not move it down the last 5" and supposedly this means there is no air in the system, according to the manual. I guess the three rams will have to be pulled and am not looking forward to this. There was a comment above about the "length of the shaft must be the right length...." but I have no idea how to get at this and there is nothing in the manual.

 

[aussieflash]

Re: Trim Question - Motor Runs - but no tilt/trim

Has it worked before??? or did you receive in this condition.

 

[RRitt]

Re: Trim Question - Motor Runs - but no tilt/trim

does the motor conitue to fell if you apply additional downward pressure? this can either be by running the boat. The propeller pushes down on engine any time you are in gear moving. Or you can just try putting your weight on the engine near the skeg somewhere. If the engine is rock solid in trim then it may be a problem with tilt ram. More likely the engine goes down but at less than 1/10th of the rate and it is harder to notice. That typically means a pump failure in the check valve circuit.

as regards you manual release. It needs to be seated but not tightened. if you torque it then the tip may break off in the hole and then you're in for a big job. but if the nylon has a burr then it may not be seated. typically, there is about a 1/10th of an inch gap between aluminum and base of collar. If you have 1/4" of more then back the plug out and check for clean threads.

 

[Woodbinekeith]

Re: Trim Question - Motor Runs - but no tilt/trim

The motor is new to me - bought late last fall so did not want to start it up and risk freezing. Came privately but from a licesned marine mechanic who went through the wole thing and said the tilt/trim was working fine. Seemed like a nice guy and helped me install the motor on my boat. Never again Hear it run and better yet, operate it on the water. Checked the manual release and the end/threads seem to be OK and I backed it off a bit from being snug. The going price for this valve is $60. The motor is held rock solid in the trim position so not likely the problem is with the two trim pins. Much more likely it is with the tilt ram. Do I have to pull the whole tilt/trim unit to get at this? From the manual it seems that it is necessary as it shows the power steering nut coming off along with the bolts through the transom and 3 bolts at the bottom of the frame. It shows the motor being held in place with a C clamp but this seems pretty minimal, given the weight of the motor.

 

[RRitt]

Re: Trim Question - Motor Runs - but no tilt/trim

it should be snug. It probably doesn't matter. In my experience the mylon release has to come out 3-4 turns before it causes problems.
here is what I would do.

I would back out manual release 3-4 turns until the valve opens. then I would throw a rope over a branch and manually raise/lower the engine 2-3 cycles. At top of every stroke I would check fluid. If there is a large air bubble this should force it back into reservoir where it will float up. Don't run the trim motor with release valve out. This can damage the orings. After going through a few cycles then I would tighten the release valve and try the switch - checking fluid at top again. Your ram has a floating piston and can trap large amounts of air. When the air hits the pump gears it can cavitate. We are trying to make sure this is not happening. Once you have eliminated air cavitation then you can focus in on pump.

or -
i would go buy a manual that covers your specific engine and trim system and follow their troubleshooting chart.

 

[Woodbinekeith]

Re: Trim Question - Motor Runs - but no tilt/trim

Thanks for all your help. I've come to the conclusion that it is the tilt ram that needs rebuilding but there doesn't seem to be anyone in Calgary who wants to rebuild it at a reasonable price. Even parts are an atrocious price and have to be ordered from afar. It seems as with most other appliances, it is a matter of replacing the entire unit. I'm looking at iBoats Sierra and CMG units. I have the latter on a 30hp Johnson and it works great.

 

[RRitt]

Re: Trim Question - Motor Runs - but no tilt/trim

I doubt it is the ram. the seals in the ram tend to last 30 years while the seals in the pump tend to last 20. What does happen though is that the top seal on ram lets more water get by as you lower the system. This water accumulates and leads to pump failure. So the pump is typically the problem but the top seal is the cause. In the end, they both should be repaired together. I forgot if you said what system you have. The single ram systems can be rebuilt for under $250. I think you can still buy a rebuilt kit from the dealer for the three ram system so I would be surprised if a local marina said they could not fix a three ram trim. As regards discontinued parts and service for mercury trim - check ebay. They are still the best place for used trim and service.