I haven't done this with exactly that model of control, but I have done it with dual-lever/single-function flush-mount controls and also dual-level/dual-function top-mount controls. (Yes, my present boat has twin engines and dual stations -- with only two dual-function levers at each station).
In each case it was "theoretically" as easy as attaching the new cable exactly where the old one was attached.
A few real-world complications that might arise and associated suggestions:
-- There may, or may not, be enough slack to pull up the control head to disconnect the cables and it is very hard, if possible, from the bottom. So, you might need to disconnect on the engine and transmission to make slack.
-- The cables are thick and, depending upon the routing, it may or may not be easy to pull them through. You have a choice between pulling the new one with the old one or pulling a string and then using it to pull the new one.
-- Regardless, of which way (pull by string or pull by cable), may I recommend that you pull an /extra/ string with the first and maybe second one you pull? This way, if something goes wrong when pulling the /last/ one, you've got a second chance without undoing work.
-- May I suggest removing the terminating loop and stop nut before pulling the cable through (new and old). It'll make it easier to pull -- and less likely for anything to unscrew and get lost along the pull. If you don't remove it, may I suggest taping them on with good duct tape?
-- May I suggest not throwing out the old terminating loop and nut, in case you need them on the new cable.
-- May I suggest, if your cables are secured by E-clips at the engine and/or transmission, that you have some spares. It is probably a good time to replace them, too. And, they like to get lost.
-- May I suggest, before starting to pull anything, use nail polish (preferred) or electrical/duct tape (back-up plans) or something else that won't pull off to mark the position of the stop nut on the old cables and also to measure the distances.
-- May I suggest checking the cable paths before pulling. People like to zip tie things to the cables. You may want to relocate these or secure them differently. If bundles are ziptied with the cables, at the least, you'll want to ziptie the bundle independent of the cable before cutting the zip ties. This way, you can easily secure them otherwise or when done without having wires everywhere.
-- May I warn you that, in many cases, cables run through circuit breaker, fuse, and/or junction areas. This was the case on my last boat and my present boat, for example. The lower helm, in particular, tends to have controls with the associated cables, as well as electrical switches and breakers. Be careful with these pulls. You don't want the metal of the cable shorting the back side of breakers -- those are a lot less circuit protected (maybe only main, maybe only on shore, depending upon where short happens). The same is true of wiring terminal blocks. Try to carefully control the side of any cable as it passes through any area like this, using a 2nd person as necessary. Maybe insulate the end before pulling it through, e.g. a lot of electrical tape. Make sure whoever working in the box/area has the skill to recognize the hazards and do so safely. Disconnecting shore power, powering down inverters, turning off the generator, and shutting off battery switches is a pretty darn good idea in many cases.
-- When assembling the new cables, you'll want to set the stop nuts correctly. The goal is to give the new cable the same amount of movement as the old cable.
-- If you are keeping the old ring terminators, or the new ring terminators are /exactly/ the same, you can measure to the stop nut. Otherwise, you want to measure to the center of the old terminator ring, and set the center of the new terminator ring to be in the same place, even if the lock nut gets set differently.
-- I think the easiest way to do this measurement is to take the old cable and pull all the slack to one side, so that the lock nut is against the sheath on the other side. Then, measure from the sheath to the lock nut on the side where the cable sticks out. Now you know the amount of cable movement your old cable had. If you pulled off the nuts to pull the cable, you can put them back on to your mark for measuring. If your ring terminals are a different size, you can compare them to know how much to adjust the lock nuts. Just measure from the end of the sheath to the center of the ring with the old terminator, put the new ring terminal on and adjust the center of the ring to be in the same place, and measure the difference. Then make that adjustment to the lock nuts on both sides. It may be the case that you end up with the same amount of distance from lock nut to tip of cable -- but this isn't the critical measurement.
-- If the old lock nuts didn't have the same distance between nut and tip, you can adjust it for symmetry before reinstalling, just keep the cable extension the same. But, also be sure it wasn't done that way for a reason, e.g. some type of mechanical circumstance with the terminators.
-- Take pictures of everything before you start.
-- Label all of your cables before pulling on both ends, near the ends. Otherwise you'll have four cables and guessing as to which one is which.
-- Keep track of what gets connected to the top vs bottom of the controls. The two sides move opposite directions.
-- In some controls there are multiple attachment points to set how much control movement it takes to cause the cable to move a certain amount. For this reason, may I suggest marking the point with some nail polish before removing each cable. This way, when you look back later, you know exactly which point was used without having to figure it out or realizing there were more options than you remember.
I know i made this sound crazy hard -- but it'll really be very straight-forward once you start. I think.
Cheers!
-Greg
