Honda BF75A Trim Tilt Randomly Raising engine

[NautiCloud]

Hi,

I have a 1998 BF75A.

This past weekend the trim tilt suddenly and unexpectedly raised the engine as I was steaming out to fish. I could override it with the down button from either thee remote or the engine cowl, but then it would randomly raise it again.

Strange thing is that on the way home after a beautiful day fishing it stayed down the whole time.

I checked the engine cowl switch harness and it appears to be good. No corrosion.

I have not yet checked the remote switch harness.

The trim/tilt motor itself has a small crack near the mounting screw, but the wires going into it seem fine.

It seemed to happen when I hit a wake or a wave, but conditions were pretty calm. Also, this only happened in the AM, not in the PM, so I am wondering if the water completing a circuit somewhere dried up during the day.

Could it be the relay? I am able to operate the trim/tilt from both the remote and the cowl in both directions (up and down).

TIA

Nauticloud

 

[bcbit01]

Re: Honda BF75A Trim Tilt Randomly Raising engine

You have a loose connection or a bad solenoid that is causing the trim circuit to close. Trace and check all the connections. If you have a book, test the trim solenoid. There may be more good advice for you but this is all I have.

 

[Anchor Marine Repair LLC]

Re: Honda BF75A Trim Tilt Randomly Raising engine

Hi,

I have a 1998 BF75A.

This past weekend the trim tilt suddenly and unexpectedly raised the engine as I was steaming out to fish. I could override it with the down button from either thee remote or the engine cowl, but then it would randomly raise it again.

Strange thing is that on the way home after a beautiful day fishing it stayed down the whole time.

I checked the engine cowl switch harness and it appears to be good. No corrosion.

I have not yet checked the remote switch harness.

The trim/tilt motor itself has a small crack near the mounting screw, but the wires going into it seem fine.

It seemed to happen when I hit a wake or a wave, but conditions were pretty calm. Also, this only happened in the AM, not in the PM, so I am wondering if the water completing a circuit somewhere dried up during the day.

Could it be the relay? I am able to operate the trim/tilt from both the remote and the cowl in both directions (up and down).

TIA

Nauticloud

A relay has to receive voltage to engage. They can only create the elctro magnetic field when given 12+ volts to the positive side, and a good ground is present. If it could fall apart or corrode inside, it would be incapable of completing th circuit, even if it had voltage (pushed from some switch). So that eliminates that.

Tilt/trim buttons will get water inside them and complete the circuit.

A little known fact: A 2 way rocker switch connects opposite the button you push. In other words, it rocks/connects down when you push the up. So that's why your TnT is going UP on it's own. One of your switches has enough rusty water in it to complete a circuit. It's not something you could see too obvious on the outside of the switch, unless the rubber seal has a split.

Divide and conquer. Take one switch out of the equation when this is happening (disconnect it) at a time. Have the quick release areas for the switches accessible for easy unplugging.

If you have a digital meter, checking resistance between the up and down circuit will tell you which is corroded.

For example, you test the continuity for the DOWN circuit and it's 0.002 OHMS (which is right). Then the UP has 32.17 OHMs- that's corrosion/resistance. It will work when you push it, but any 12 volt switch should have less than 0.005 OHMS. So that 32+ shows an abnormality.