1980's Mercury 175 power trim

[baja184ss]

Howdy,

Picked a project 1981 Baja 184ss from a friend with some known issues, however I did ski behind it last year so I figured it would be viable to work on.

Power trim doesn't work, solenoids click but no movement. Jumper cable power directly to hydraulic motor leads & basically nothing, motor is bad. One screw for the hydraulic motor is easily accessible, the other is well hidden behind the transom bracket. I read on another forum that I can remove bolts from the right transom bracket & slide it out of the way to get at it. This motor is on a jack plate so I wouldn't be able to totally remove the bolts in question to allow the bracket to slide, so I think I'm stuck. Trying to avoid using an engine lift, pulling both transom brackets or pulling the jack plate would both have me rigging it up.

1: Can I get to that rear hydraulic pump screw without getting an engine lift involved?

I cannot find a direct replacement for this electric motor, I would like to avoid rebuilding the one I have. it It is the rectangular Eaton motor like this: https://www.perfprotech.com/mercury...ctangular-motor/assembly/586/400?umodel=10131

2: Can I use a generic replacement for this motor or do I need to find that exact rectangular one?

Have to manually raise the motor bc no trim/tilt. As I have it half way and am using a jack, hydraulic fluid shoots out of the top of the center tilt cylinder. I now know there is a relief valve I should have used before I blew that seal. Nice.

3: cylinder rebuild kits are $120 for like 6 O-rings, is that a joke?

Engine serial: 0A958460
I know its 1976-1988, I was thinking its an 84 from the SN & range but I'm not 100% sure.

Thanks!

 

[Dukedog]

first your motor is:

1986 Outboard 175 [ELPTO]​

these are really good, stout motors when healthy.. 200's got nothin' on 'em....

​

next tha jack plate should not come inta play at all when ya wanna pull tha one side of tha clamp.. ya really need some type of support on tha motor doin' it that way anyway.... jus from experience we found we were way ahead by pulling tha whole motor "away" from tha boat ta access everything ta repair... jmo and good luck with it.........

 

[baja184ss]

first your motor is:

1986 Outboard 175 [ELPTO]​

these are really good, stout motors when healthy.. 200's got nothin' on 'em....

​

next tha jack plate should not come inta play at all when ya wanna pull tha one side of tha clamp.. ya really need some type of support on tha motor doin' it that way anyway.... jus from experience we found we were way ahead by pulling tha whole motor "away" from tha boat ta access everything ta repair... jmo and good luck with it.........

Thanks for help with the year! Do you know if I can get by with a generic electric trim motor? I know these came with round and rectangular electric motors so I’m thinking I can use something as long as it bolts up. I see plenty online for $100 or so, I just don’t wanna order something I can’t use.

 

[Dukedog]

most everything i'm familiar with is tha single ram stuff.. most 3 ram stuff that we fixed we jus went with a whole clamp and trim assy. replacement.. hydraulics we left ta a whole 'nother hyd. shop.. drop off and pick up when they called.. i do know that tha main thing ya gotta make sure of is tha little drive gear on tha pump.. there seems ta be a coupla different ones on both round and square pumps... thats all i got.. good luck and hope ya get it right....

 

[Chris1956]

ARCO and Sierra make aftermarket trim motor replacements. Your 1986 motor likely has a 3 wire PTT motor, unless it has been replaced before. 3 wire PTT motors use 2 solenoids to power them. Newer PTT motors are 2 wire, and use 2 relays to power them. The wiring harness is different, but either is mechanically compatible with your PTT unit.

When you order a new motor make sure it is the same as your current motor, or it comes with the new wiring harness to adapt it to your motor. The installation is not difficult.

You might check the PTT unit where it pivots, as you trim the motor. On an older motor like yours, the casting wears at that point. If she is leaking, and the casting is intact, new orings can seal the leak. If the casting is chipped or otherwise worn, aftermarket whole PTT units are available.

If it is just the PTT motor that is bad, the easiest way to remove it is to remove the starboard transom bracket. That allows access to the allen screw that is close to the jackplate. You can stick a piece of wood undet the tilt tube to support the engine when you remove the transom bracket. Obviously you need to loosen the steering cable nut and the tilt tube nut on the starboard side, and remove the bolts holding the transom clamp.

 

[baja184ss]

ARCO and Sierra make aftermarket trim motor replacements. Your 1986 motor likely has a 3 wire PTT motor, unless it has been replaced before. 3 wire PTT motors use 2 solenoids to power them. Newer PTT motors are 2 wire, and use 2 relays to power them. The wiring harness is different, but either is mechanically compatible with your PTT unit.

When you order a new motor make sure it is the same as your current motor, or it comes with the new wiring harness to adapt it to your motor. The installation is not difficult.

You might check the PTT unit where it pivots, as you trim the motor. On an older motor like yours, the casting wears at that point. If she is leaking, and the casting is intact, new orings can seal the leak. If the casting is chipped or otherwise worn, aftermarket whole PTT units are available.

If it is just the PTT motor that is bad, the easiest way to remove it is to remove the starboard transom bracket. That allows access to the allen screw that is close to the jackplate. You can stick a piece of wood undet the tilt tube to support the engine when you remove the transom bracket. Obviously you need to loosen the steering cable nut and the tilt tube nut on the starboard side, and remove the bolts holding the transom clamp.

Thanks Chris!

I found this inexpensive PTT motor, it says it directly fits this year & power and has a 2 wire conversion like you were talking about. (yes mine has 3 wire)
https://www.motorcityreman.com/mercury-rt05028-46757-186757.html

I'll be sure to check for casting wear at the pivot. It wasn't visibly dropping when it was off of the lock but it did lower all the way over night. The seal I think is damaged had an audible pop and a spray of fluid out the top when I was cranking it back up, I am thinking its the top hydraulic seal.

Your explanation for the pivot helped a lot. This is my first big motor after a few different tiller boats so my I was still thinking like this is a clamp bracket.