82 50 hp tilt and trim

redneck joe

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Chris1956

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If the motor pumps up under load, then the pump is probably fine. You probably have a bad control valve or leaking piston seals. Both will cause the cylinders to leak down.

Crowleymarine shows both as NLA.

As far as I know, the control valve is not rebuildable by us amateurs. The cylinders had a rebuild kit some years ago. It was a bunch of orings and a teflon piston seal. The piston seal required a special tool to install it.

Maybe you can find a used PTT unit and cannibalize?
 

redneck joe

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If the motor pumps up under load, then the pump is probably fine. You probably have a bad control valve or leaking piston seals. Both will cause the cylinders to leak down.

Crowleymarine shows both as NLA.

As far as I know, the control valve is not rebuildable by us amateurs. The cylinders had a rebuild kit some years ago. It was a bunch of orings and a teflon piston seal. The piston seal required a special tool to install it.

Maybe you can find a used PTT unit and cannibalize?
if it is seals, gaskets are old so not sure cannibalize would work.

how could i test to see what the issue is?

To my original question would the link (or some other unit) work? I realize if the rams on the motor are leaking that is an seperate issue.
 

Chris1956

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If the piston seal in the trim cylinder is bad, no pump will make it hold trim. Ditto for the control valve, although, I never had any issue with that item.

You may be able to find an old trim cylinder rebuild kit. It will take some looking. Then you will need to isolate the leaking piston seal to the correct cylinder. This can be done, with some plugs.

If the trim goes up when the motor is in gear and boat is on plane, the pump is likely good. Of course, if the trim cylinder piston seal is real bad, the leak could mask a good trim motor.

I always thought that the PTT cylinders on the 50HP motors were shorter than the ones on the 80/85/90/115/150 HP motor, which I know share trim cylinders. You would need to check this.

You might start investigating whether you could switch out the midsection and transom brackets on your motor for a newer one with the built in PTT.
 

jimmbo

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My motor drops slowly when on trailer and of course faster when under way. Are they semi universal and or how do I fine out what is compatible? Mine has a trailer heater, that does not work ans really don't care but would this work?
Trailer Heater?
Your motor is dropping, so what is with the Transom Button Kit?

There should be plenty of 2nd Hand Parts/complete Systems available
 

redneck joe

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Don't know how heater got in the sentence, was supposed to be trailer setting on the switch.
 
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redneck joe

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If the piston seal in the trim cylinder is bad, no pump will make it hold trim. Ditto for the control valve, although, I never had any issue with that item.

You may be able to find an old trim cylinder rebuild kit. It will take some looking. Then you will need to isolate the leaking piston seal to the correct cylinder. This can be done, with some plugs.

If the trim goes up when the motor is in gear and boat is on plane, the pump is likely good. Of course, if the trim cylinder piston seal is real bad, the leak could mask a good trim motor.

I always thought that the PTT cylinders on the 50HP motors were shorter than the ones on the 80/85/90/115/150 HP motor, which I know share trim cylinders. You would need to check this.

You might start investigating whether you could switch out the midsection and transom brackets on your motor for a newer one with the built in PTT.
Yeah everything works, just slowly lowers when on trailer and faster when on the water running so I'm going to go with the cylinders are allowing bypass.

I'll try to figure out a rebuild kit.
 

jimmbo

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Have you got the Factory Service Manual? I used to have one for my Inline 6 and it had a Section for the Power Trim Systems. Included were Drawings of the Hydraulic Systems
 

redneck joe

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This appears to be the one I need?


 

jimmbo

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Looking at the Table of Contents, to me, it looks like a Selock/Clymer Manual. My Factory Manuals

I would trust this manual far more
 

redneck joe

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Looking at the Table of Contents, to me, it looks like a Selock/Clymer Manual. My Factory Manuals

I would trust this manual far more
just ordered, glad it didn't sell.

It even had a pic of the manual open to the TnT section... :)
 

redneck joe

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ok the repair on this is fairly far down on my list as it does operate up so shallow water and trailering are covered.

Two updates. One the up switch quit working. THe trailer switch works fine so assuming bad connection up under there. i did cut wires and splice during the refit.

But as I thought i remembered it doing, last trip out all day the trim held fine, while running and while anchored. When i got home I popped the trailer supports and it did sink but only halfway like it did on the water and held for a full day plus like that. Now what would that be?
 

Chris1956

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The trim switch will only operate if the trim limit switch is closed. The trailer switch should operate at all times.

The trim limit switch is located on the starboard trim cylinder and bracket. They often break at this time of it's age. I do not know of a replacement, however, as long as the trailer button works, there is a work-around.

I expect the leak down can be caused or made worse by the power of the motor pushing the motor it to tilt down.
 

redneck joe

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Yeah but it wou.d drop, in like two hours. Now it stayed up for a day and a half?

Didnt really pay attention when running. I have a pin in the second hole so that's where it stays un.ess I go shallow.
 

redneck joe

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Been watching ebay for a few months and the new old stock has been well north of 100 bucks each cylinder, snagged two from diff sellers for the price of one.

Never cracked into hydraulics before...
 
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