I have an I/O with a merc. 5.0 and alpha one outdrive. This week my trim gauge started only working if the unit was all the way up or down and every once in a while in between but not accurately. My Mercruiser manual doesn't say anything about it. I checked my gauge and all connections seem fine. Where is my sending unit and how do I test or troubleshoot it? Thanks for the help.

The trim sending unit is on the tilt gimble on the out drive. I'm not a boat mechanic but maybe this link will help. <BR><a href="http://www.sterndrives.com/replacing_trim_senders.html" target="_blank">http://www.sterndrives.com/replacing_trim_senders.html</a> <BR>Good Luck

Thanks for the link, helped a lot. I had no idea changing the sending units would be so involved, and you have to replace both the power trim sending unit and the power trim limit switch. Oh well, gonna have to wait until after the weekend.