Power Trim & Tilt and in gear protection controls

[Jimbo]

Hi All,

I have a 150hp Optimax, Mercury engine, which recently developed an intermittent starting and trim fault.

Chasing and testing wiring I found a corroded link on the ignition barrel, to one of the two wires going into the back of the throttle/gear system. The two ends had been rubbing together intermittently, and my poking around dislodged them.

A new bullet connector solved that problem - and tests at the moment show she is starting and running fine, and the trim and in gear protection is working.

However, given that the problem was intermittent, I want to be sure I have actually fixed it - and I'm confused!

Going into the back of the control box is two wires, both of which then go into the ignition barrel (this is where the break was). I can't find any more wires coming out - just the throttle cable, and the gear cable.

I can't see how two wires can control in gear starting protection, up tilt, and down tilt - to my mind that needs at least four.

Am I being blind and missing the trim wires, or is there some sort of clever system at play here?

Cheers!

[martini]

My guess would be that yes, you are being blind! Your two wires going from control box to ign barrel I assume are yellow/red and will be for the neutral switch. There should be an additional 3 pin plug for the trim switch which plugs into the engine harness.

[Jimbo]

Cheers martini - it's nearly stopped raining so I'll go and have another look!

Could those two wires perhaps have caused a short somewhere, which inhibited the PTT? Is one of them likely to be a common ground including the PTT? Yes, they are yellow/red.

[martini]

Originally Posted by Jimbo

Cheers martini - it's nearly stopped raining so I'll go and have another look!

Could those two wires perhaps have caused a short somewhere, which inhibited the PTT? Is one of them likely to be a common ground including the PTT? Yes, they are yellow/red.

It's unlikely, the 2 circuits are pretty much completely separate, apart from the fact that theyre both bundled together in the main engine harness that goes back to the motor.

I have a wiring diagram for a typical installation if you need it.

[Tim M]

What sort of throttle is it, side or top mount?

[Jimbo]

Originally Posted by Tim M

What sort of throttle is it, side or top mount?

It's a top mount throttle, and martini is quite correct, I was being blind. I've found the trim wires!

I guess that means I have fixed the starting problem, but potentially the trim problem remains, so it's back to the drawing board.