850 Merc hydraulics

[850Merc]

Bump. I have a 76' Mercury 850 with two hydraulic arms (one on either side of the motor) pretty sure its just tilt, but I was having trouble finding new hydraulic lines without including the word "trim" in my searches. Thanks for clearing that up.

 

[Chris1956]

Re: What is the difference between tilt and trim?

Re: What is the difference between tilt and trim?

850Merc, Your system is both trim and tilt, using the same hardware. When you first start raising the motor from all the way down, you are "trimming" it. After a while the trim limit switch is supposed to stop trimming. You then need to push one more button to "tilt" the motor. usually the trim limit switches break.....

 

[aspeck]

Re: 850 Merc hydraulics

Started a new thread for you, 850, so you wouldn't resurrect an old one or hijack someone else's.

 

[850Merc]

Re: 850 Merc hydraulics

850Merc, Your system is both trim and tilt, using the same hardware. When you first start raising the motor from all the way down, you are "trimming" it. After a while the trim limit switch is supposed to stop trimming. You then need to push one more button to "tilt" the motor. usually the trim limit switches break.....

Thanks, I think I understand more thoroughly now. My boat came with one of these, but for some reason I just assumed that trim was completely different than tilt.



You can see why this might seem a bit confusing to someone new to boating!! (UP, UP, OUT, IN) on three buttons?!?

Started a new thread for you, 850, so you wouldn't resurrect an old one or hijack someone else's.

Sorry about the hijack. I was just trying to show people that information is out there, you just have to look for it.

 

[850Merc]

Re: 850 Merc hydraulics

As long as this is my thread now. I might as well take advantage. I bought a four pack of hydraulic hoses yesterday for the boat, the old ones were kinked and all of the protective plastic had been eroded away by the sun.



Sorry iboats, ebay beat you by about $30. I love this site more than you can imagine, and I will (and have) purchased through here for several items. Anyways I can't wait to get this portion taken care of ASAP.

Can anyone tell me the procedure for bleeding these new hydraulic lines? I assume that there are bleeder nipples on each of the hydraulic rams, and a reservoir on the pump.

Also, being my first boat, what type of fluid (brake I assume).

Input is much appreciated.

 

[GA_Boater]

Re: 850 Merc hydraulics

850 - Send me a PM with an email addy. I have Installation instructions for your two ram TnT.

On your buttons - the bottom two are TRIM control and the top two are TILT control. Huh? OK, the bottom "IN" moves the motor to lower the bow, the center "OUT" to raise the bow. Kinda "in" the water and "out" of the water. "OUT" trims the motor until the trim limit switch makes and the "OUT" is disabled.

On to Tilt - The top switches are pressed at the same time to tilt the motor up for trailering. To lower from trailering, press the bottom/IN button.

Hope I didn't assume you wanted to know how the buttons work. But IHTH.

BTW - NO Brake fluid.

 

[850Merc]

Re: 850 Merc hydraulics

850 - Send me a PM with an email addy. I have Installation instructions for your two ram TnT.

On your buttons - the bottom two are TRIM control and the top two are TILT control. Huh? OK, the bottom "IN" moves the motor to lower the bow, the center "OUT" to raise the bow. Kinda "in" the water and "out" of the water. "OUT" trims the motor until the trim limit switch makes and the "OUT" is disabled.

On to Tilt - The top switches are pressed at the same time to tilt the motor up for trailering. To lower from trailering, press the bottom/IN button.

Hope I didn't assume you wanted to know how the buttons work. But IHTH.

BTW - NO Brake fluid.

That helps immensely, I'm sure when I get this thing on the water it will come to me very quickly. I'll PM my email address right now, thanks GA!!

 

[GA_Boater]

Re: 850 Merc hydraulics

The trim limit switch seems to fail a lot. Probably because it gets hit by splashing water.

 

[Chris1956]

Re: 850 Merc hydraulics

Those systems originally called for 5W-30 motor oil. A lot of folks used ATF. Not sure it makes any real difference, as long as you don't mix them. The pump is self bleeding. Each cylinder must be bled with the bleed ports facing up to allow the air to bubble up and escape. There are no bleed nipples, like on a auto brake system.

 

[850Merc]

Re: 850 Merc hydraulics

Those systems originally called for 5W-30 motor oil. A lot of folks used ATF. Not sure it makes any real difference, as long as you don't mix them. The pump is self bleeding. Each cylinder must be bled with the bleed ports facing up to allow the air to bubble up and escape. There are no bleed nipples, like on a auto brake system.

Thanks Chris, GA sent me a really nice PDF that runs through the entire installation process for the TnT. It calls for either 10W30 or 10W40. I guess I was way off with thinking brake fluid, I guess I am more used to working on cars and the only hydraulics there is the brake system...:facepalm:

The trim limit switch seems to fail a lot. Probably because it gets hit by splashing water.

Would it be easier to test it while the motor is off the boat, or just put it back on and test it then? I'm not 100% sure its something worth fixing, I just want to weight the options.

Again thanks guys!!

 

[GA_Boater]

Re: 850 Merc hydraulics

You should be able to put a meter on the switch leads to see if it makes and breaks.

 

[850Merc]

Re: 850 Merc hydraulics

I had a chance to test the switch over the weekend and it works fine. The more I see things on this boat the more I think it didn't get used much before I took ownership.

 

[850Merc]

Re: 850 Merc hydraulics

hydraulic line routing is a bit of a pain on this thing. Last night I was able to get the lift arms installed and the lines attached. I had to be creative getting the lines fed through the tiny access holes, but I was able to make it work.

The lines are very rigid, and don't really have any room for error (or misaligned) between the pump and rams. I put the fittings on loosely so that I can twist them later while installing the pump.

My question is: is there an easier way to do this? If I had installed the lines on the pump before putting on the TnT bracket it may have helped, but things get bound up pretty quickly.

 

[850Merc]

Re: 850 Merc hydraulics

I have the line installed and the pump placed under the splashwell, now I need to figure out how to go about bleeding the system. From what I am reading the hydraulic rams have a "self bleeding" valve that will automatically bleed the arms during use.

Is there anything else I need to know before filling the system with 10W30 and running it up and down?

The wiring was pretty confusing when I got the boat, does the pump just hook directly up to the battery? and remain "live" all the time? or should it be controlled by the ignition system?

 

[GA_Boater]

Re: 850 Merc hydraulics

TnT is always live. Then you can tilt or lower the motor without turning on the key. The install instructions I sent - Page 24 has the bleeding steps. Pretty simple. Get her dancing on the stern.

 

[Chris1956]

Re: 850 Merc hydraulics

Trim pump is self bleeding. Bleeding the cylinders is a manual process, four steps long.

 

[850Merc]

Re: 850 Merc hydraulics

TnT is always live. Then you can tilt or lower the motor without turning on the key. The install instructions I sent - Page 24 has the bleeding steps. Pretty simple. Get her dancing on the stern.

Thanks GA, I'll make sure to re-read that part before I attempt to bleed it. Do you just wire the TnT directly to the battery or do you put in a fuse panel? I want to put in a battery switch that I can completely separate the battery from the boat without having to physically pull it.

Trim pump is self bleeding. Bleeding the cylinders is a manual process, four steps long.

I have a mightvac hand pump bleeder, I'm assuming I can hook it up to the bleeders on the cylinders and just draw it through (while making sure I don't run dry in the reservoir. Unless there is something even more dastardly to deal with? I suppose I was them fully compressed (engine down) while do it to get all the old stuff out.

 

[GA_Boater]

Re: 850 Merc hydraulics

Also on page 24 top - a 90 amp and 20 amp fuse are used. Both are mounted on the pump. The battery leads are connected directly to the battery.

Bleeding is basically fill the pump with the motor in the trailer position (all the way up) lower it and raise it several times, enduring the reservoir stays full.

 

[Chris1956]

Re: 850 Merc hydraulics

What GA suggests for bleeding is not what is recommended by Merc, however, a lot of folks do it that way. Does it work, probably works OK, but does not completely bleed the cylinders.

No way I can think of to use using a hand-bleeder. There are no nipples like on automotive applications. In addition the bleed screws are not always in the right position.

Here is bleeding procedure: Fill PTT reservoir. Remove one slotted screw next to grease fitting on top of cylinder. Run PTT motor in down direction until oil w/o air emerges. Reinstall bleed screw. Repeat with other bleed screw. Refill reservoir.

Now remove both PTT cylinders from their mounts. Turn them over so bleed screw next to hoses faces up. Remove a bleed screw. Run PTT motor in up direction until oil w/o air emerges. Reinstall bleed screw. Repeat with other PTT cylinder. Reinstall cylinders and fill reservoir.

 

[GA_Boater]

Re: 850 Merc hydraulics

What GA suggests for bleeding is not what is recommended by Merc, however, a lot of folks do it that way. Does it work, probably works OK, but does not completely bleed the cylinders.

No way I can think of to use using a hand-bleeder. There are no nipples like on automotive applications. In addition the bleed screws are not always in the right position.

Here is bleeding procedure: Fill PTT reservoir. Remove one slotted screw next to grease fitting on top of cylinder. Run PTT motor in down direction until oil w/o air emerges. Reinstall bleed screw. Repeat with other bleed screw. Refill reservoir.

Now remove both PTT cylinders from their mounts. Turn them over so bleed screw next to hoses faces up. Remove a bleed screw. Run PTT motor in up direction until oil w/o air emerges. Reinstall bleed screw. Repeat with other PTT cylinder. Reinstall cylinders and fill reservoir.

Chris - the procedure is what the Merc instructions say that I sent to 850, 75281168-Mercury-Outboard-Tilt-Manual. Different cylinders? :noidea: But experience beats the factory everytime. Thanks.