[Ballard35]

I have a 1998 Mariah Shebah 4.3L mercruiser. My trim works fine going down and in the trailer position. However, my trim up button will not work. I dont even hear the trim motor working when i push the up button. I dont know a ton about these issues so if someone can explain what they think the problem is in detail (and possibly how to fix it), i would appreciate it. Thanks in advance.

[Dredd]

It's often the trim limit sensor. It's a fairly common problem. Here's a bunch of topics about it.
https://encrypted.google.com/#sclien...171c9fee8a0a41

[Ballard35]

Thank you much for your help. It appears that since the trailer button is working, the problem is the trim limit switch. Does anyone know where this is located on the boat?

[Snoopinrob]

There are two sensors about halfway down the outdrive I believe, one on the left and one on the right that are round. It's one of those two but can't remember which one but I think it might actually say on the sensor, if not someone on here who actually knows what they're talking about can tell you. Good luck with it!

[Dredd]

Yeah, the senders are back where Spooninrob described. Where your drive pivots on the stern, essentially (on each side of the gimbal ring, technically). Unfortunately the drive has to come off in order to replace them. Occasionally, from what I've read, the setting is just off and adjusting that isn't a difficult job. The trim limit one is the one on the starbird side. It will have a metal pointer and some notches on it for adjustment.
Removing the drive requires special tools so you'll want to rule out other possibilities, such as bad switch, before you prepare to replace the senders.

[darkcalling]

Yes they sometimes also just need a good cleaning but make sure you mark the current settings that way if you just have to clean it up or adjust you know where your base setting was, good luck.

[mikeyt]

Here's a good instructional link from MercStuff.com