power trim tilt system on 89 mercury 70 hp very slow trim tilt up

[dan_crosby]

my mercury 70 horse 1989 has the 3 piston type system that mounts between the transom brackets seems to go down good motor makes noise but trims up very slow checked oil thats good.... kinda seems to jump a little when trimming up any ideas or solutions thanks

 

[aussieflash]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

Sounds like air in system,or dirty check valve.Is it just while trimming or all the way up for trailering.Look for visible leak in system,usually out of main ram cap.You might even find your cap seals have blown and are half way up piston rod.Try bleeding up and down a few times,then check level...if level is down refill then repeat process.

 

[dan_crosby]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

There is no visual leaks in the system and I've tried bleeding it with no success and yes the trim is very very slow the tilt isn't too bad this dirty check valve where would I find that? Thanks again for your help

 

[aussieflash]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

Could also be loose or faulty manual release valve.Check its snug tight only.(plastic slot plug on starboard side)access through hole in transom bracket.Fill plug also needs to be snug tight.
Trim check valve located on port trim rod.Cap removed with pin wrench.First release pressure from fill cap and manual release valve.Dont forget oil pan as it will get messy.

 

[dan_crosby]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

ok i will try that... ive got the motor off the boat now because the steering bracket is very stiff to steer trying to get that off to clean out the old gunk out i tried to heat the tube up and put new grease in but once it got cold it seized up again... whats the easiest way to get that bracket off?

 

[aussieflash]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

Are you using the grease nipple.Photo might help.

 

[dan_crosby]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

Yeah I was pumping the grease in through the grease fitting when I get home ill get a picture for you... Does the powerhead have to come off to pull the steering bracket out?

 

[brandon110]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

yes powerhead off. on your power trim system, just checking you are aware that then the motor is riding on the 2 shorter pistons it will go slower and when you get to the point when it come off those pistons it will go up much faster? there is a service bulliten on the manual tilt screw on some of these trim sustems. if i get you serial number i could check that for you. that may be your issue. also if you havent its a good idea to put some grease on the balls on the end of the 2 shorter shafts as to it allows them to move much easier and if there super dry they will make a grinding sound as you go up and down.

 

[dan_crosby]

Re: power trim tilt system on 89 mercury 70 hp very slow trim tilt up

yeah i know the trim is supposed to be slower than the tilt but you can barely see the motor move on the two short rams.... where do i find the serial number on the trim system? it seems to jump as you trim up like its slipping or something? the tilt works fine...and i will put grease on those two balls on the rams.. thanks