Merc I/O - what goes down won't come up
 

Hey all...

This is my first post on this forum.

I have a 94 Diablo, 4.3 V-6 and Merc I/O. The trim controls work in the "down" direction (meaning trim works when the switch is pushed "down"). Lately they do not work when I push the button "up"; however, the "trailer" button works as it should and will raise the outdrive unit from any point including fully "down"

I see a "sticky" at the top of this section, but can't read it at work due to our stupid firewall :mad:

I'll read it when I get home but seems to me that if the "trailer up" and "regular up" share the same hardware then a bad button on my throttle handle thingy could be the culprit?

Any info appreciated. Thanks!

Re: Merc I/O - what goes down won't come up
 

Do you hear the solenoid click when you use the trailer control?
May help to narrow down the problem.

Re: Merc I/O - what goes down won't come up
 

No... I don't recall hearing anything....

Re: Merc I/O - what goes down won't come up
 

I'm sympathetic. Mine failed completely while i was on the water this weekend. Had a hell of a time getting the boat back onto the trailer & out of the water without damaging the skeg....

Mine started acting up when i was prepping the boat to go into the water. At first i thought it was the throttle trim switch but I ended up jiggling the wires back at the trim motor & it started working again. It then quit completely on my return trip & nothing i could do would get it to work. Ended up having to remove the trim rams so we could manually lift the outdrive.

Re: Merc I/O - what goes down won't come up
 

I've got the same issue with a Mariah that just purchased.
I took apart the trim-up switch and cleaned up the electrical contacts, which didn't help.
Since the 'trim-up' and the 'trailer' buttons use the same solenoid, and your trailer button works, your solenoid is good.

The difference, electrically, is that the trim-up button goes through the trim limit switch mounted on your drive before it connects to the solenoid. Either the switch is bad, the switch wiring is bad, or the swich isn't set properly.

I'll be taking my drive apart this weekend anyway to take a look at some other issues, so I'm planning on just replacing the trim limit switch at the same time.

Re: Merc I/O - what goes down won't come up
 

And i think that you can only buy the Trim Limit & Trim Sensor as a kit so you might as well replace them both while you are in there. :)

Re: Merc I/O - what goes down won't come up
 

I see that...
Not that I was looking for additional work, but as long as I've got the bugger apart might as well take care of replacing some of those "consumable parts" that have a history, or are likely to fail a week after I've got her all back together.... as my luck usually goes.

Re: Merc I/O - what goes down won't come up
 

Thnaks for the input. I have not verified the switch on the throtttle handle, but plan to this weekend.

The limit/sensor looks a little scary to replace. Not sure I whether would tackle that or take it to a shop. My trim position gage has never worked since I owned the boat - so would definitely attend to that as well if my "no up" issue is in the limit/sensor

Re: Merc I/O - what goes down won't come up
 

I just did both sensors on our 302 last week. it is a 2 man job and take a bit to test and adjust perfectly. cost of the sensors are about $100