trim trouble
 

I have a 1999 z222 7.4L with a bravo drive. At times when adjusting the trim it won't work, if I trim quickly the opposite way and then back it works fine. Anyone have any thoughts before I dive into the seloc manual...thanks. I have already checked the fluid levels.

Sounds like a minor short in the switch wiring. Unfortunately, I don't have much experience or suggestion for you.

I did find a power distribution plate mounted to the transom behind my batteries that looked like it was getting corroded. I took off each nut and wire terminal, sanded it down, and replaced them. This wasn't because of a short, just routine maintenance. I'm not even sure if the plate powered the trim hydrolics or not. I don't know how easy it is to track the wiring, but I'd start looking for that and all the points of connections. Over time (specially in a marine environment) those terminals can start getting corroded and cause what you're experiencing.

Is the problem always in the same direction? - ie. in order to trim down you have to trim up first? Does it change if you are sitting at idle, or at speed?

I'd check the controls, sometimes they can get crud in them after years of use. I'd unhook the batteries, and run the heck out of that trim switch, up, down, up down, and make sure there's no sticking. This will help clear it out. Hook the batteries back up and try again, see if there's any improvement. Also, do you have the transom mounted trim control in the back on the swim deck? That could possibly be a source to track down as well. If you can't make any progress with it, I'm sure any Mercruiser service facility could fix it for you.

Indykoch, that plate you found is for the Mercathode system, it's the for the sacrificial anodes all over the boat (corrosion protection) :)

So aquaknot, did you get your trim problem resolved? I'm curious to know what the problem was and what it took to fix it.

fixed
 

thanks for the reply's. I opened the seloc manual and it suggested a possibility of air in the lines and I should raise and lower the trim 5 times, still had trouble. I then raised and lowered the drive using the trailer trim at the strern,all the way up, all the way down, 6 times, fixed, no more problems...................thanks to all for your suggestions