Mine won't pick up the depth when running over 20mps

Most depth finders have auto range and manual range. In auto range the transducer sounds the bottom and automaticly will switch the range. If the range is set to manual then its probably picking up the bottom upon start-up and going back to your manual range setting. I'd start there..
Good luck Aloha

Mine did that and I had to tighten the connection better from the wall cable into the input.

see this causes and fix it. God bless you
Air filter:
If the vacuum cleaner won't pick up dirt and has no suction the air filter might be clogged. Remove the filter and either clean or replace it as needed.
Exhaust Filter If the vacuum cleaner won't pick up and has no suction the exhaust filter might be clogged. Remove and clean the filter, replace it if its torn or damaged.


Vacuum Hose If the vacuum cleaner won't pick up and has no suction the vacuum hose might be clogged. Remove the hose from the vacuum cleaner, stretch it out straight, shine a bright flashlight in one end and try to see light through it. If no light can be seen, use something to run through the hose and free up the obstruction.
Vacuum Bag If the vacuum cleaner won't pick up and has no suction the vacuum bag might be full. Clean or replace the bag as recommended by the manufacturer.

Dust Cup AssemblyIf the vacuum cleaner won't pick up and has no suction the dust cup assembly might not be installed tightly, or it might be cracked or broken. The dust cup must seal tightly in order to produce the right amount of suction. If it is cracked or broken, replace it. Most glues and adhesives will not successfully seal the crack.
Blower Wheel If the vacuum cleaner won't pick up and there is no suction, the blower wheel might be jammed or broken. Check the blower wheel to be certain it turns freely. If it doesn't, check to see if there is anything rubbing against it. If not, but it's hard to turn, the motor is most likely the problem.

Call service engg.

Think of where the transducer is fitted on your boat . As turbulence is the only problem you need to worry about. It needs too be on the transom but in between the lower 2 chines

Try taking the pipe off completely and blowing up it. This worked with mine

Go to:
http://service.mattel.com/instruction_sheets/I7007.pdf

I just found a screw that fit nice and tight then stuck a tooth pick in the hole to get the depth then went to ace hardware and picked up some allen head screws worked like a charm just be sure that your screws are 1/8 inch shorter than depth

I havew a Minn Kota trolling motor on a Z21 Ranger. Minn Kota has a built in (puck type) transducer on the motor. I have a lowrance 135x on the front. The lowrance will read the temp but will blink the depth. I switched out the depth finder with another 135x with the same results. I have a 522c gps unit networked together and mounted on the console that works fine. Any suggestions on the problem with the 135x?

First easy thing to check, are you using the correct length needle.
If this is not the problem then somehow the needle bar has moved and the the needle depth is to high or the timing is wrong..
Unless you really know what you are doing then I am afraid a sewing machine tech needs to reset the needle depth and subsequently the timing.