I was wondering, I dont have a guage on my k-planes. But I just hold them down till I think they are all the way down, and hold them till I think they are all the way up. But that just causes the pumps to cavitate. Is there anyway I can use a trim limit switch, like on a outdrive to keep it limited?

No.

well ok then..lol

The only way to limit them is to make a sleeve to go aroung the ram. If you want to limit the up travel, then clamp it to the outside of the ram. If you want to limit the downward travel, then you will have to put it on the inside of the ram. Merc. has a similar internal limiter for the outdrive rams to prevent them from triming up to high and hitting the platform, etc.
Eddie