Trim won't go full down

[jumpjets]

My outdrive is behaving oddly. It has been stored in a mostly down position since september. I gave it a function check today, and it wouldn't go all the way down. This is the position it gets stuck in.



This outdrive will trim all the way up to the trailer position with no issues. It will also smoothly and quickly trim itself down to this position. Once it gets here, it stops moving and it makes the typical change in sound.

I remember the trim system being capable of going further down than this. I thought that it could go full down so that the polished chrome part of the rams was invisible.

Is this a possible malfunction in the down pressure relief valve? Is there an issue with the rams themselves? Is this worth troubleshooting, or should I just buy a new assembly?

 

[alldodge]

Re: Trim won't go full down

My outdrive is behaving oddly. It has been stored in a mostly down position since september. I gave it a function check today, and it wouldn't go all the way down. This is the position it gets stuck in.

View attachment 221727

This outdrive will trim all the way up to the trailer position with no issues. It will also smoothly and quickly trim itself down to this position. Once it gets here, it stops moving and it makes the typical change in sound.

I remember the trim system being capable of going further down than this. I thought that it could go full down so that the polished chrome part of the rams was invisible.

Is this a possible malfunction in the down pressure relief valve? Is there an issue with the rams themselves? Is this worth troubleshooting, or should I just buy a new assembly?

It looks like your drive is coming in contact with the Gimbal at the bottom

 

[thumpar]

Re: Trim won't go full down

What is the history? The drive doesn't match the bellhousing. I would guess something is hitting if the pump is still running.

 

[jumpjets]

Re: Trim won't go full down

What is the history? The drive doesn't match the bellhousing. I would guess something is hitting if the pump is still running.

History: I bought the boat 4 years ago. Everything worked just fine. 3 years ago, I replaced the drive with a rebuilt drive, and replaced the gimbal bearing due to a water leak. A mechanic checked my work and said it was good to go. 2 years ago, the trailer trim feature quit working. I could trim the drive all the way up to the trailer position using the regular 2 way trim switch.

In Sept 2013, I winterized and parked the boat. The drive was trimmed down to the position in the picture. The trim worked 100% when I parked it. I tested it today, and it wouldn't go down any further. I tried "exercising" it multiple times. I went through the merc service manual and did troubleshooting steps on the pump assy. It passed.

I had the drive off today, and the bellhousing had full freedom of movement with and without the drive on. I tested the hyd rams without them bolted to the drive. They stop in the exact same place and don't fully retract. It's not the drive itself that's binding.

This trim system could be the OE 1990 parts, making them 24+ years old. I don't know when the trim hyd oil was changed last. It hasn't been in the past 4 years though.

 

[thumpar]

Re: Trim won't go full down

Gimbal bearings don't cause water leaks. Did you replace the bellows?

 

[jumpjets]

Re: Trim won't go full down

Gimbal bearings don't cause water leaks. Did you replace the bellows?

I replaced a leaking bellows and I replaced the drive since it had a seal fail, and it got filled with water. I replaced the gimbal bearing since I was in there anyways. It seemed like the prudent thing to do.

 

[thumpar]

Re: Trim won't go full down

With the drive on disconnect the trim rams and run it up and down by hand to see if something is binding.

 

[jumpjets]

Re: Trim won't go full down

With the drive on disconnect the trim rams and run it up and down by hand to see if something is binding.

Yep, I did that this afternoon. The drive had it's full range of motion. It would go all the way down with gravity assist.

 

[Bondo]

Re: Trim won't go full down

Yep, I did that this afternoon. The drive had it's full range of motion. It would go all the way down with gravity assist.

Ayuh,.... Look real closely at the area where the rod goes into the ram,...
Mineral build-up in the gland nuts can cause that bindin',....

Chances are, that if ya splash the boat, 'n run it, ya may not have a problem, as the prop thrust will push it through the tight spot,...

The trim pump uses Hi-pressure to lift the drive, 'n relatively Lo-pressure to push it down,...

 

[alldodge]

Re: Trim won't go full down

I had the drive off today, and the bellhousing had full freedom of movement with and without the drive on. I tested the hyd rams without them bolted to the drive. They stop in the exact same place and don't fully retract. It's not the drive itself that's binding.

This trim system could be the OE 1990 parts, making them 24+ years old. I don't know when the trim hyd oil was changed last. It hasn't been in the past 4 years though.

I would take the rams apart, probably got some corrosion in there

 

[bspeth]

Re: Trim won't go full down

you guys don't think the limit switch got turned somehow?

 

[Bondo]

Re: Trim won't go full down

you guys don't think the limit switch got turned somehow?

Ayuh,... That only works in the Up circuit,....

 

[bspeth]

Re: Trim won't go full down

roger that

 

[jumpjets]

Re: Trim won't go full down

Ayuh,.... Look real closely at the area where the rod goes into the ram,...
Mineral build-up in the gland nuts can cause that bindin',....

Chances are, that if ya splash the boat, 'n run it, ya may not have a problem, as the prop thrust will push it through the tight spot,...

The trim pump uses Hi-pressure to lift the drive, 'n relatively Lo-pressure to push it down,...

I'm definatley going to give this a try. There is a very, very trace amount of grime and discoloration right at the spot where the motion ceases on the polished portion of the ram.

I hooked a rachet strap up to the skeg, and I put a little bit of forward pressure on the drive, to try to persuade it forward. I ran the trim down, to see if the additional persuasion from the rachet srap would help out. No joy. I'm going to try it using the prop thrust like you mentioned, though.

I would take the rams apart, probably got some corrosion in there

I think that is a likely candidate, but I find it odd that both rams stop in exactly the same spot, even when the drive isn't attached to them.

 

[jumpjets]

Re: Trim won't go full down

Ayuh,.... Look real closely at the area where the rod goes into the ram,...
Mineral build-up in the gland nuts can cause that bindin',....

Chances are, that if ya splash the boat, 'n run it, ya may not have a problem, as the prop thrust will push it through the tight spot,...

The trim pump uses Hi-pressure to lift the drive, 'n relatively Lo-pressure to push it down,...

Bondo,

You sir are correct again! I splashed the boat today, and prop thrust pushed through the tight spot. My trim is fully functional now, and I didn't end up spending a fortune on new rams!

 

[Bondo]

Re: Trim won't go full down

Bondo,

You sir are correct again! I splashed the boat today, and prop thrust pushed through the tight spot. My trim is fully functional now, and I didn't end up spending a fortune on new rams!

Ayuh,..... That happens on rare occasions,.... Good Luck with it,....