yamaha f100 tilt trim

My 2000 Yamaha F100 will not trim down when you run it all the way up. You have to open the screw to bleed pressure. Trim goes up and down as long as you dont run it all the way up. I've cleaned it and changed fluid. Now what?

[boats.net]

Replace both main valves in trim unit(only remove and replace one at a time)using the one in this link Yamaha Outboard Parts 2003 F90TLRB POWER TRIM & TILT ASSY 1 Diagram

Replaced both valves with new and improved ones from parts link and works great. Thank You

[RD209]

f100 tilt trim problem

Hi,
I have the exact same problem with my 2000 f100.
my question is which parts did you have to change from the list that was provided? I don't see a part called main valve.
Thanks.

[boats.net]

It's part number 67F-43802-00-00VALVE SUB ASSY

[RD209]

thanks, I appreciate the help

[wdrucker]

You may not need both valves, I had the same exact problem as original poster and was able to replace only the valve facing astern (which is super easy to do as it only requires a big fat screwdriver and about 60 seconds if the boat is out of the water.) This one valve completely solved the problem and my T&T works as original.