Yes ... another tilt and trim thread.

[Archer59]

1994 Merc 75 hp 0G014879

The tilt slower going down than up.

The fill cap shredded some pieces into the unit.
I blew air through everything when it was apart.

I replaced all the o-rings through out the unit.
Voltage at solenoids is 11.24 for both green and blue.
I'm still purging air out, I suppose when you fill the cylinder three inches shy of top that leaves a lot of air.
Only thing I can think of next after air is out is the motor.
I can detect a difference in the hum or noise the motor makes between up and down. (could be normal)

Anyone ever take the pump apart?
I suppose there could be a piece of filler cap in there but I used a lot of air through it.

Just looking for suggestions.
Thanks,
Nick

 

[Archer59]

Re: Yes ... another tilt and trim thread.

When I had the unit in the vice it would go up fine.
Would not go down.
Installed with motor weight would go down.

 

[RRitt]

Re: Yes ... another tilt and trim thread.

curved shards of filler cap can be the kiss of death for rocker arm pumps. They get lodged into manifold and disrupt oil flow to such an extent that rocker arm action is unreliable. If you have blown them clear then pump should operate smoothly in both directions. If not, you will notice difficulty changing directions. Personally, if I see a shredding filler cap then I throw the pump into trash. It can never be made 100% reliable again. There will always be that lingering doubt about whether or not a shard of plastic is still lingering in the hidden passages of manifold. That said, if there weren't any shards then you may be okay. Chunks of debris and bits of grit will blow clear. It is the 1/4" and longer curved shards that jam into corners and won't come out.

It is normal for the motor to make a different sound in one direction than the other. What you watch out for is frayed cable jackets, rust near gaskets, and noisy bearing. The motor typically doesn't last much longer when any of these show up.

 

[Archer59]

Re: Yes ... another tilt and trim thread.

Does anyone know if you can take the pump off the manifold to take a look?

 

[Archer59]

Re: Yes ... another tilt and trim thread.

Looking for schematic of pump

 

[Anchor Marine Repair LLC]

Re: Yes ... another tilt and trim thread.

Looking for schematic of pump

Here's a good link for ya. Give it time to load. It's a lot of information.

Boatinfo - Mercury Service Manual for 75--90-100-115-125 hp

 

[Anchor Marine Repair LLC]

Re: Yes ... another tilt and trim thread.

When I had the unit in the vice it would go up fine.
Would not go down.
Installed with motor weight would go down.

When a tilt/trim won't go down on it's own, it's because there isn't enough fluid in the reservoir. Up is the point that a large amount of the fluid is consumed into the trim ram. That's why you HAVE to fill the reservoir only when the unit is fully in 'UP' position.

Another way to put it is think of your pump like a set of pedals on a bicycle. You're only using one pedal to make the complete power cycle when your fluid is low.

 

[Archer59]

Re: Yes ... another tilt and trim thread.

I have a full reservoir.
Used the manual release valve to cycle it down.
Then ran it up and checked fluid again.
Talked to a mechanic and he feels there is a piece of filler cap lodged in the pump some where.

Just can't find a schematic for the pump and manifold.

Must be a secret.

 

[RRitt]

Re: Yes ... another tilt and trim thread.

When a tilt/trim won't go down on it's own, it's because there isn't enough fluid in the reservoir. Up is the point that a large amount of the fluid is consumed into the trim ram. That's why you HAVE to fill the reservoir only when the unit is fully in 'UP' position.

Another way to put it is think of your pump like a set of pedals on a bicycle. You're only using one pedal to make the complete power cycle when your fluid is low.

not really. When you lower a trim system the piston shaft retracts and displaces fluid. The reservoir becomes more full. As you raise a trim system the piston extends and the fluid level in reservoir decreases.

The net result is that systems low on fluid will raise until the reservoir runs too low and then lift no further. The same system will lower fine from that point because the lowering increase fluid level inside reservoir and even just one or two bubbles is enough to get it started. At the same time, you do not want to add fluid to a lowered system because the reservoir might be pressurized. The filler cap and MRV are made from plastic and the threads will frequently strip if you try to loosen them under pressure. Additionally, if the system is not low on fluid then oil may spray out including your eyes and face.

 

[RRitt]

Re: Yes ... another tilt and trim thread.

I have a full reservoir.
Used the manual release valve to cycle it down.
Then ran it up and checked fluid again.
Talked to a mechanic and he feels there is a piece of filler cap lodged in the pump some where.

Just can't find a schematic for the pump and manifold.

Must be a secret.

no schematic needed.
two gears spin and push fluid around. each side of gear has a hole into fluid reservoir with a ball bearing.

When the gears spin one way then the ball bearing is pulled clear of hole and fluid is sucked in from reservoir. When the gears reverse direction the ball is pushed into hole and fluid flow is forced into cylinder. One side of gears pushes ram up and other side pushes it down. Hence you end up with a reversible hydraulic piston.

The manifold is made from a solid block of aluminum. Fluid passages are drilled at intersecting angles to direct the oil. Once drilled, the manifold is flushed and the drill entrance plugged with a steel ball.

If the manifold becomes contaminated with debris larger than 1/8" then it should be either redrilled or thrown away. The passages are not fully accessible without removing steel balls and there is no reliable method of detecting and removing debris that may be lodged deep inside manifold.

 

[Anchor Marine Repair LLC]

Re: Yes ... another tilt and trim thread.

Here's a link to a schematic.


It's a full manual for your motor. Page 376 is where you're looking for your own knowledge. It loads slow!

Boatinfo - Mercury Service Manual for 75--90-100-115-125 hp

In case the link don't work, copy and paste this =http://boatinfo.no/lib/mercury/manuals/75-90-100-115-125.html#/380

Unfortunately, Mercury doesn't support their tilt and trim systems much past 5 years old. These will break their rocker arm often. And that simple little part will render the whole thing useless. Many parts are NLA, so you end up making your own rocker or just fitting theright o-rings, etc.

It's easy to access the top of the pump, just go through the manual. There's not much to service there, as stated by a previous post. But you'll see any debris right away, to eliminate that posibility..

Good luck

 

[Archer59]

Re: Yes ... another tilt and trim thread.

I actually have the trim unit on page 331.
Serial number of my motor is 0G0...

I have no problem taking the trim unit apart, 3 times this week.
Just have never opened up the pump, wondering if springs and parts will fall out.

 

[RRitt]

Re: Yes ... another tilt and trim thread.

I actually have the trim unit on page 331.
Serial number of my motor is 0G0...

I have no problem taking the trim unit apart, 3 times this week.
Just have never opened up the pump, wondering if springs and parts will fall out.

yes springs and balls will fall out. take it apart slowly. it is easiest to see where stuff comes from if you slowly lift the shiny round part off of the black base. Have the black base sitting on a 12x12 square so that it is impossible for loose parts to roll off. At this point in time, you have nothing to lose. To my knowledge I'm the only guy getting into the pumps and if you sent it to me as a core i would throw it away (debris). So take it apart slowly and maybe you can bring it back from the dead. If you have enough patience then surely you could clean it up with pipe cleaners or something. But ... here's the thing ... the rocker arm doesn't work right if there is debris partially blocking a fluid channel. You have to get ALL the debris. A bit left behind may shift and cause future failure.

 

[Archer59]

Re: Yes ... another tilt and trim thread.

Update.... took pump apart and there was a piece of plastic in the spring keeping one of the ball from closing.
Working again.

 

[RRitt]

Re: Yes ... another tilt and trim thread.

Update.... took pump apart and there was a piece of plastic in the spring keeping one of the ball from closing.
Working again.

you got lucky. they usually lodge in manifold and the pump never works again.