Pontoon Boat & Deck Boat Forum

I have a 2001 Honda BF115 on my Bennington. The trim switch on the side of the shift/throttle lever has quit working. The trim button on the side of the motor cowling still works. What is weird is that I trim it to where I want it using the cowling button but, at the end of the day, the motor is trimmed almost all the way back in when no one touched the trim.

So how hard is it to replace the switch assembly in the handle and what is causing the motor to be trimmed back in?

Had a boat that the switch shorted out in the handle, and would trim the lower unit down (sterndrive boat), but you would hear it working. I'm not sure if the on engine and trim on the handle are fused separate or not, if they are I would check that first. As for trimming back down it sounds like a leak in the cylinder. Do you have any sign of oil in the back of the boat after it trims itself down?

[quote="mpilot"]Had a boat that the switch shorted out in the handle, and would trim the lower unit down (sterndrive boat), but you would hear it working. I'm not sure if the on engine and trim on the handle are fused separate or not, if they are I would check that first. As for trimming back down it sounds like a leak in the cylinder. Do you have any sign of oil in the back of the boat after it trims itself down?[/quote]

I agree, the trimming back down by itself (not running the motor) sounds like a leaking cylinder to me.

I changed a trim switch out on a Yamaha control several years ago. It wasn't hard at all.

Thanks everyone. No sign of oil. I won't have opportunity to take the handle apart until the weekend. I'll let you know what I find.

There is a manual trim screw on your trim unit you may want to check. If it isn't tightened down snugly enough it may be allowing oil to slip by to the side of the trim.

Finally had a chance to take the OMC binnacle control handle apart this weekend. The end of the assembly with the buttons is encapsulated, so I couldn't check for corrosion or a loose or broken wire. So I ordered a replacement switch.

Of course, not until after I dropped the other part of the handle in the water. ;-( Had to go into the 59 degree water and retrieve it. Was hard to catch my breath as I stood next to my dock in neck deep water feeling the bottom with my toes. Luckily it only took a few minutes to find it.

What is it about water and loose parts? Does it have some sort of magnetic-like property to attract objects?

To close the loop on this, I took the handle assembly apart and found three wires from the switch that run back into the console. I tested them with a probe tester and learned red brings full time 12V to the switch. When you press the up button, green wire sends 12V to the relay to trim the motor up. When you press the down button, blue wire is supposed to send 12V to the relay to trim the motor down. I was getting no reading on the blue wire when I pressed the down button. (I neglected to mention in my original post only the down button wasn't working.) Followed the wire down towards the console and found where it was broken. So I repaired it and now everything works as designed.

And maybe the broken wire was shorting to trim the motor down by itself. It is not trimming down by itself anymore.