2002 Merc 2 stroke 115 hp throwing up some wobleys, opinions appreciated

[desertislander]

I was out over the weekend and with a max load on board (3 kids & 4 adults) and started to get problems when accelerating. It seemed to be missing on one cylinder and struggled to get up on the plane. Once back home, I checked filters and actually changed the in line one on the engine, the main larger one nearer the tank was good as it and the plugs had only been changed a few months ago at annual service but I did pull the plugs and clean them to be sure. Back out on the water again with just two onboard I was still getting the missing cylinder. The attached photo's shows where I think I could have a problem, but not being familiar with these electric's I am not sure. In the top near the fuse area (far left 1st photo) you will see two red wires in sockets, the left one looks black inside, burnt out I think as there is some blistering on the plastic sleeve so I am assuming this is my problem. I dont really want to replace the connector until I know what actually caused it to melt/corrode

P1270981.jpg

[scottar]

What will typically cause a burn out in a connector like that is a bad connection. The connection causes resistance and current flow through resistance creates heat. Provided the entire wire hasn't burnt the insulation I would be inclined to replace it.

[bluefin59]

Check further up the harness for a sharp bend in the loom that has been zip tied too tight at the factory , it's what happened to my 60 mariner years ago it had damaged the cable enough to cause a short and burn the same cable out from the rectifier I think .... Matt

[Fed]

Although it looks ugly I don't think it would cause the motor to miss because the reds are only the positive feeds out of the rectifier/regulator, the negative comes from the rectifier/regulator to ground. Don't ask me why there are two of them but I'm sure they have their reasons.

Anyhow, the reds have nothing to do with the ignition system.

Test for compression & spark first to see where you stand or give it to your dealer.

[desertislander]

Thanks for that Fed, the compression was tested at service in May and came out at 1-135,2-140,3-135,4-135
I am on the South Morten islands so not quite as easy to drop into a dealer, round trip with car & boat on car ferry to mainland is about $300 so would like sort it this way if possible before going that way but will check the spark next, cheers

[banshee]

These things have a valve type switch (for want of a better description) that kicks them from two firing cylinders to four after about 1800rpm,my mechanic showed it to me years ago but for the life of me I can't remember where it is.He manually 'tickled' mine while it was running and it never played up again.Might be your problem,if you can find someone to tell you where it is could be a simple fix.