Looking over the serial numbers, it appears the trim sending units would of came with the original 2 wire electrical bullet connectors design not the 3 wire electrical weather pack connector design used for later model digital trim designs and different transom to engine combinations.
Since nothing really changed parts wise as in buying wrong/different parts and both smart craft and analog trim gauges where working at the same time before working on the boat and then all of a sudden one engine side still worked and the other engine didn't work seems to indicate there might be a communication loss possibly between the master and slave engine settings whether it be a missed/unconnected connecting cable running between the two engines or maybe just the feature settings within the smart craft gauge/s itself/themselves.
If I recall correctly the starboard gauge / & engine should be the master set up and you have to set one up before the other especially now that a master reset has been initiated to one side.
If possible, since one side possibly worked after installing the two engines, are you able to see how the wires are connected for comparison to the non working side?
Though there are a few options for trim sending unit designs, I'm pretty sure the newer designed 2 wire sending units could run the digital gauges nowadays as yours ' if correct shows it to be true.
A smart craft manual should help suggest what order to configure the engine and trim settings. Do you have yours? There are some that you can find online if in need of one.
Below is some other info that's good to know incase you're unable to make this work again.
http://www.offshoreonly.com/forums/g...it-switch.html
HP Transom Assembly sender - iboats Boating Forums
