Sounds like you may have a ground problem. You have rebuilt the supply side of the system.
Suggestion: Make sure the engine is grounded properly to the frame ground (same ground as battery negative). Easy to do. Connect a set of battery jumper cables from the engine (or starter housing) to the ground terminal coming off the battery.
Also is the starter properly grounded? Ground connections are just as important as positive side connections.
I have an 1845C and it hasn't missed a beat as long as I can remember.
Click Click Click means that either you don't have enough capacity (high resistence) at the starter or the ground side does not have a good path back to battery (high resistence). Both very important. Starter relays also burn internally over time which can create high resistance inside the relay therefore not allowing enough current through relay to spin a high current motor ( like the starter-250 to 300 amp approx).
Hope this helps.