Evinrude Tilt/Trim issue

[kcm805]

I have a loud popping/creaking noise coming from the main piston of the tilt/trim hydraulics for an Evinrude 115 (early 80s v4 crossflow). I verified with a mechanics stethoscope and it is definitely coming from the red circled area the entire time the engine is moving up or down (worse when its moving faster and off of the 2 smaller trim rods). When the engine is all the way up, i can start trimming down but it wont go down, its like its hung up on something. the hydraulics seem to be working though (noise and letting pressure off the main cylinder). If i give it a little push it then slowly drops (while creaking) down to where it should be then continues trimming down normally (video shows this). Fluid was topped off and unit has been cycled many times. There is also a little bit of air pressure that comes out every time when i crack the fill plug (normal?). Sorry for the crappy video quality, had to downsize it i order to email to myself. sound is clear though. Fluid you see is from me spraying PB blaster on the upper pin (initially thought that's where the noise was coming from). Also, the rust on the electric motor housing looks bad in the pic but its just light surface rust.

video of sound: https://youtu.be/5lUbnxUwiuE

Thanks,
Ken

 

[w2much]

That is some sound. It sounds like the creaky old door hinge in a house or gate. It seems as you have tried to explore the issue so dont mind my suggestion. Are you certain that the pins holding the tt unit in place are free of corrosion and have proper lubrication. You checked with a stethescope which may nullify where I am going with this but sound does travel. If it were the piston scraping you have a problem. But the piston, cylinder and O rings would be so bad and there would be no hydraulic pressure . I dont think the noise coming from the pin has been alleviated. Heat the pin area several times spraying a wax or lubricant or penetrant with the heat source removed. As it cools it will suck in some lube or whatever although you may melt the bushings. Alternately , remove the pin to look at it.. Are the bushings still there and functioning . Let us know what you find. .

 

[Fed]

I drizzled some outboard oil on top of my 70Hp top pin until the noise stopped.
Re-visit the top pin.
I think corrosion gets between the nylon bush & the bush eye causing the bush to get squashed too tightly onto the pin.
Lubing helps but dismantling & fixing properly after proving that the noise is coming from there is better.