Tilt/trim (popular topic!)

[Dennis4b]

Hi everyone,<br /><br />I have a question regarding the trim system for an Alpha 1 outdrive, Mercruiser 470 engine, 1984.<br /><br />Trim stopped working at some point, so I got a new armature (brushes were basically gone and their wires toast, inside of armature looked bad). <br /><br />Then, put it back in place, and I wire the blue and green wires (big one from trim motor) directly to a good battery positive, and make sure the trim unit is properly grounded so as to bypass all wiring, switches, solenoids/relays, etc.<br /><br />Now, trimming one way (emberassing, but I don't remember which one!! ) goes smoothly, so I guess that's the pressure release direction.<br /><br />Trimming the other way gives funny noises, inconsistent (i.e. they change), and usually overheats the thermal protection in the armature, after which a 10 second wait will give you another 2 seconds of trim <br /><br />Brushes are good, motor is good, clean, oiled, etc. But it consistently overheats and trims badly in the one direction.<br /><br />Do these sound like classical symptoms of air in the hydraulic fluid? Focused only on electrics so far (not my boat - yet!).<br /><br />Otherwise the outdrive *will* eventually trim all the way up or down, so can I assume the hydraulic housing doesn't need a rebuild yet? <br /><br />So, does air in the fluid cause overheating of the trim motor as well as irregular trimming and screeching noises? <br /><br />Regards and thanks!<br />Dennis

 

[clanton]

Re: Tilt/trim (popular topic!)

I would disconnect the hoses, and raise the outdrive up and down by hand should move smoothly, crud gets under the seal and seal housing and will lock the cylinder thght enough that the hyd pressure will not move cylinder.

 

[Dennis4b]

Re: Tilt/trim (popular topic!)

Except the boat is in the water and a haul out would suck <br /><br />I'm hoping its only air. Get to try in a few hours.

 

[clanton]

Re: Tilt/trim (popular topic!)

Air in system should not cause over heating, over loading the motor is whats causing the overheat, the over load may be caused by pump pumping max pressure and the cylinder not moving or line plugged with trash.

 

[Dennis4b]

Re: Tilt/trim (popular topic!)

Hi, thanks for the responses.<br /><br />Sorry I wasn't clearer, I meant that if an air pocket would be present is it possible the motor will overheat due to overloading (overrevving I guess) trying to compress the air instead of pushing the fluid.<br /><br />Blocked passage ways sound like a possibility, is there a way to fix this while the boat is in the water? I guess disconnecting hoses, take out the oil, which will drop the drive down all the way, is there a good way to clear the tubing then (compressed air or something?). Then refill with oil and bleed the air bubbles out? <br /><br />Also, is this (vintage 80-84 Alpha 1) a self bleeding system? Is there a vent that should be open while trimming up and down a few times?<br /><br />Hoping to get the factory manual this saturday and have a play with it. Thanks for all replies!

 

[Bondo]

Re: Tilt/trim (popular topic!)

Hi Dennis,<br />the 1980/84 is a model 1, alpha did not come out till 1985..... some of the mod. 1's have a reverse lockout mounted on the transom.... if you by-pass all the wiring to test your pump, you also by-passed the reverse lockout..... at this point you are trying to pump oil through a somewhat leaking reverse lockout... these systems will self purge most air problems them selfs with normal usage...i think you will find that if you reconnect all the wireing it'll go back to working right....<br /><br />i once blew the side out of a trim cyl. by bypassing the rev-lock.......i guess mine wasn't leaking at all....<br /><br />Bondo