Mark, I purchased a shop manual for my new motor, and it has some wiring diagrams that may be of some help to you. You are more than welcome to borrow it . Bob
Attached are photos of the main wire harness for the Optimax 225. The end with the red cap goes to the engine. There are four wires that come out of the side of the plug. These are brown, tan, GRN/WHT, and BLU/WHT. The green/White and Blue/White are identified on the Merc. color chart as being "trim up" and "trim down" wires. The end with the black plug is at the throttle and is the plug for the tach harness. sticking out from the plug are four wires - Red (constant power), Tan (temperature), GRN/WHT, and BLU/WHT. Inside of the 5-pin plug is a purple (switched power), black (ground), Gray (tach pulse), and tan/blue (which I believe is an ANALOG trim position lead, based on my research). I don't recall the color of the 5th wire that goes to the plug. I've ordered the tach harness - perhaps it will come with directions - although that would not be Mercury-like. I'm not yet certain as to what, if anything, I am supposed to do with the "trim up" and "trim down" leads, since the trim switch is built into the throttle handle. That's it for now... Any input anyone has based on these pictures would be great. I've already received much guidance on and off the forum, which is very much appreciated. My goal in posting as much of this as I can is to have a place for others to pick up the information later. Markbano
The extra trim leads on the control are for mounting an accessory trim switch. Fishing boats often have trim switches up on the bow so you can trim the motor from up there. You do not have to do anything with them.
Mark, Many if not most of these big engines are rigged with a foot throttle and some sort of steering wheel mounted trim switches, either the turn signal type of the ones mounted on the spokes of the wheel. Once in a while you will find a foot operated trim. The idea is that since the motor has the potential for high speed and all of the issues that come with that, the driver needs to have both hands on the wheel. The binnacle is only used for shifting in this case and may even be replaced with a billet shifter with no neutral start switch so the motor can be started in gear for less wear on the gear case. The heavy high pitch props with solid hubs are a little hard on gear cases. The trim wires are probably for the additional trim switche(s). Since the ski boats run low pitch props and need good speed control they usually use the binnacle for throttle. jim
Mark, do you already have the adapter wire harness that will except the 8-pin w/h main plug and the 14-pin main plug that is on your motor? Edd
Edd I apologize - not sure if I understand your question. I've got the wire harness that came with the throttle unit which has the plug-in on the motor end and the 5 pin tach harness plug next to the throttle. I've ordered the tach harness. I haven't yet purchased the SC1000 monitor or the digital cable because I'm not sure what I need to order for that. There are different monitors and different data cables and I haven't figured out yet exactly what I'm supposed to use for this motor. Any advice you can provide would be much appreciated. Thanks! MarkBano
Mark Sorry it took so long to get back. Put the Twin Verado's and a Safety boat in the water today just to check everything before the team heads for the Kentucky Derby on Tuesday. Also worked on one of the triples. I'll post a picture of it when it's done. Took these pics today hope they help. You have one boat to rig and I have two singles and two triples to rig. HELP party
