switch boxes

[tomoad]

On a mercury motor the switchboxes have a white/black wire that connect them together, it is located on the top left part of the switchbox. What does this wire do?

[j_martin]

It ties the bias circuits together so the timing of the two boxes remains more or less in sync. That same wire is used for anything that modifies timing, for instance an idle stabilizer module, or an advance module.

hope it helps
John

[tomoad]

Thanks, John I have a low miss, around the 2500 to 3500 rpm range. & it clears up at 4000 rpm. Yesterday if found this wire that was about apart so i replaced it, just curious what this wire done. i thought it was a bias wire but wasn't sure. May not cure my problem but atleast the wire was replaced. I also tried a different ECU, & the same problem missing in the 2500 to 3500 range exists, just trying to track the problem down. it sounds like its 4 stroking. the problem isn't that bad, just trying to fix it

[j_martin]

Don't think this wire will make any difference. It'll run without it.

Do a run for a mile with it misbehaving, then kill the engine suddenly. Check the plugs, and go for injectors, bleed lines, or whatever in the different cylinder.

If, when you check the plugs you find one squeaky clean, you might have a "water in the cylinder" problem.

hope it helps
John

[whipper]

Also could be stator starting to act up. Mine started this way. it was just a miss then after a few weeks turned into a bog down at 4000rpm, then a matter of finding out what it was and was the stator in the end. Theres so many things that act the same way it makes it tough. I bought a manual and asked as you are there are some great knowledgeable folks hear. Youll get it worked out. Mine also at wot would go flat,stop pulling rather sharply. Suspected fuel at first.

[props4u2]

You probably do not have a problem at all. Every Mercury engine I've ever ran has a harmonic (rough running) area between 3 and 3,500 rpm's above that, all is fine.


Lee