Thread: power trim on 04' 50hp Mercury

Check and make sure manual screw didn't back out.

Originally Posted by Mbsbeek

Check and make sure manual screw didn't back out.

not sure where that screw is, but I will try and look it up, thanks

I had a leak on a hydraulic cylinder on my trim, and the suggestion that was given on here was to get some transmission fluid with stop leak in it. First, drawing out the old fluid, then replacing it with the transmission with stop leak. I did this a couple times, and it seemed to recondition the seals, and mine hasn't leaked since I've done that fix. I will see if I can find the post with the information.....as I also came here to those that know and got the help that saved me hundreds of dollars!

Your manual valve screw is in a hole on the side of your tilt trim. With a big flat tip screw driver you can loosen it and manually lift and lower the motor. Tilt it up all the way first and engage motor brace first to hold it if possible. If motor is up once you loosen it the motor will start going down.

Sent from my moto g(7) power using Crappie.com Fishing mobile app

Ok, I trimmed the motor all the way up and locked it with the safety pin, I cracked the fill screw and red fluid trickled out, I retightened it. I double checked to make sure Manual screw on the side was tight and also the one in the back of the unit, all checked out.
After doin some googling I found plenty of info on replacing a relay, I'm wondering if the relay is getting sticky, and if so where its located for replacement? I will probably have the boat out again this weekend if see if it acts up again. last Sunday I was dodging stumps in a creek off the Ohio river in Indiana.

Originally Posted by Tom 513

Ok, I trimmed the motor all the way up and locked it with the safety pin, I cracked the fill screw and red fluid trickled out, I retightened it. I double checked to make sure Manual screw on the side was tight and also the one in the back of the unit, all checked out.
After doin some googling I found plenty of info on replacing a relay, I'm wondering if the relay is getting sticky, and if so where its located for replacement? I will probably have the boat out again this weekend if see if it acts up again. last Sunday I was dodging stumps in a creek off the Ohio river in Indiana.

Just make sure your boat is level to the (level) ground before opening the fill screw, so that the fluid in the unit is level when checking to see if you need more fluid.
Relays are usually on the driver's side of the motor. Pretty easy to remove & replace (I did it on my 90hp Merc). Their cost should run between $15 - $20 each.

I've also read that a jerky trim could be a sign of a loose tilt tube nut. ( what causes tilt & trim to jerk - Google Search )

Valvoline High Mile Dextron ATF With Stop Leak And Seal Conditioners. Red jug, (Not synthetic) available in quart or gallon at Walmart or most auto parts stores. Mercury says use tilt trim fluid OR ATF.
Suck out old fluid with a turkey baster or syringe, a little hose on it might be helpful, I prefer to do this with the motor down but where you can still get to the fluid cap on the unit. If the motor is tilted up that means your piston (or pistons) will be stroked out and you won't be able to get out as much fluid. Get out all the fluid you can, refill, stroke it a couple of times, and replace the fluid again. Not much fluid in there, and don't be surprised if you find some metal in it. Follow manufacturers recommendations for checking fluid level when you are done. Do this again in a year or two, and enjoy the ride!
NOTE: The manual valve screw mentioned previously is good to review. Big screwdriver preferred. Back it out a little, lift lower unit up and down a time or two, retighten screw. Good to stay familiar with just in case you ever have a tilt/trim issue, so you can safely load your boat on the trailer and not damage the skeg dragging it up the ramp. Don't forget to keep things greased back there that turn side to side and go up and down, and under the cowl throttle linkage that goes back and forth! Like Dad used to say, "Greasy means easy, Son".

Originally Posted by TheGrandPoohBah

Valvoline High Mile Dextron ATF With Stop Leak And Seal Conditioners. Red jug, (Not synthetic) available in quart or gallon at Walmart or most auto parts stores. Mercury says use tilt trim fluid OR ATF.
Suck out old fluid with a turkey baster or syringe, a little hose on it might be helpful, I prefer to do this with the motor down but where you can still get to the fluid cap on the unit. If the motor is tilted up that means your piston (or pistons) will be stroked out and you won't be able to get out as much fluid. Get out all the fluid you can, refill, stroke it a couple of times, and replace the fluid again. Not much fluid in there, and don't be surprised if you find some metal in it. Follow manufacturers recommendations for checking fluid level when you are done. Do this again in a year or two, and enjoy the ride!
NOTE: The manual valve screw mentioned previously is good to review. Big screwdriver preferred. Back it out a little, lift lower unit up and down a time or two, retighten screw. Good to stay familiar with just in case you ever have a tilt/trim issue, so you can safely load your boat on the trailer and not damage the skeg dragging it up the ramp. Don't forget to keep things greased back there that turn side to side and go up and down, and under the cowl throttle linkage that goes back and forth! Like Dad used to say, "Greasy means easy, Son".

Perfect, great information and I will try it after tomorrows fishing and follow your instructions. You know I have a 19' Silverado that had shifting issues, I had the fluid changed to a new type fluid and all's good.

Thanks Tom 513