A few years ago, I got some used Yamaha 704 controllers for our ski teams Twin rig, with Mariner engines, one counterrotating. Before you start converting the controllers for the engines, you need to know how your engine operates. Some engine are pull on the throttle cable to go faster, others engines are push. Some lower units are pull for forward gear, others are push. Mercury, and Mariner engines, to the best of my knowledge are pull to go faster, and clockwise rotating lower units are pull to go forward. counterrotating lower units are PUSH for forward gear. Remove the cover screws. There are four of them. Move one throttle handle forward, and the other back, then carefully remove the cover. There are three screws that hold the controller together. Remove the screw in the picture, with the screwdriver in it, and turn the two controllers over, and remove the screw in the same location. There is one screw, with a nut, in the center bottom of the controllers. Remove that screw also. the controllers should come apart. controller split. The Port controller has a trim switch on the handle There are three screws that hold the lower cover on the controller. remove them. The lower cover should come off. In this picture, the screwdriver is pointing to the shift lever. Remove the cables now. Be careful not to lose the clips. It would be a good idea to have some extras, before you start this project. Remove four screws holding the throttle slide guide. Notice the position of the screws. All the previous pictures were on a controller set up for pull go faster throttle, push for forward gear, or the controller set for a Mercury counter rotating engine. The following pictures are the controller set for a normal rotating engine, and the steps to make it a counter rotating controller. This controller has levers for pull for more throttle, pull for forward gear. Remove the throttle slide guide. Use snap ring pliers to remove the snap rings from both the throttle lever pivot, and the throttle slide.
Take the throttle slide out. Loosen the throttle drag adjustment, this screw is on the outside of the controller. Remove the throttle lever. Remove the throttle drag clamp. Remove the throttle pivot, two M6 screws, 10 MM head. Remove the screw with the 10mm head, holding the shift lever. Move the shift lever from this position, to this position. Put the screw, with the big washer, that holds the shift lever back in, tightnen snugly. Put the throttle lever pivot on the other side of the controller, do not forget the spacer, and the "U" in the spacer faces the center of the controller. Put the throttle drag brake back over the throttle lever pivot. Put the throttle lever carefully on the pivot, with the drag on the outside of the throttle lever. Put the washer, and then the snap ring on the throttle lever pivot. Put the throttle slide over the throttle lever, and the bearing that rides in a track on the underside of the throttle slide. Move the controller handle into a forward gear, and give it some throttle. make sure the two levers move in the direction you want them to. Put the throttle lever slide guide in place, put the four screws in. longer screws to the bottom two holes. Put the snap ring on the pivot for the throttle slide. Now, you can put the cables on the controller. The shift cable moves first, then throttle. The shift cable is centered, and moves both in, and out. The throttle cable moves only one way, in the case of Mercury engines out. Put the three screws that pair the controller together in the controllers, then put the conteoller back on the boat. You will need to adjust the cables before running the boat. you can do a little adjustment inside the controller boxes, but most of the adjustment is done back at the engine.
Holy Crap. I got dizzy looking at the detailed pics and need to read again in detail. I will read again even though I don't anticipate twins. nice job! Kevin-
I am in the process of installing a brand new C/R lower unit on my 20 ft twin rig and spent several hours over two evenings researching on the internet how to configure the Yamaha 704 control box to work with my set up. I finally found a several year old post Daniel C had made on Scream & Fly about some electrical concerns he had with his conversion. I P.M.'d him and asked if he had also converted his control box to work with a C/R gear box and he said he did. He then offered to take apart a spare 704 box he had in his shop and take pictures of how to reconfigure it and share it with the members of this site. I didn't realize how much work it was going to be for him as he went all out with the pictures and step by step explanation of how it was done. As it is said "pictures are worth a thousand words", and in this case after seeing his write -up I feel confident in starting this project. I'd like to thank Daniel for all his work, and the detail he put into this. Bob
A quick you are welcome for the thanks. I should note that this happened because I posted in 2008 about improving Quicksilver 3000 series controllers, and user Must-Ski Motors ended up sending me 4 of the Yamaha 704 (two pair) controllers. A little more info. In this picture, above the shift lever, is a circular part, held by two Phillips screws. Remove the screws, and that part held by the screws can be positioned with the roller that fits into the throttle slide, near the top of the controller, instead of the position it is in. That converts the controller to a "push throttle cable to go faster" controller.
The basic difference between OMC and Mercs is that Mercs pull for power and OMC pushes for power. Yamaha went with the Merc system and their controls are interchangeable except for Smartcraft. I don't know what Suzuki and Honda do. I know there are alot of OMC guys in this forum but it seems to me that Merc has cornered the market and I would guess that other brands would copy the Merc system. Over the years I have had OMC's and Mercs and I do prefer the Mercs because in the day the tower of power was awesome. Not to mention now I have Merc specific tools and so will stick with what I know.
