Like the topic states I'll be replacing one walbro 255 or a 485 pump. I physically know how to do it, however on the electrical, I plan on adding a relay to how buschur has the 2nd pump come on, my question is should I rewire the feed for the 485 pump or will I be alright if I just splice in the 485 to the existing wiring that ran the 255 that I'm replacing? Thanks

The 485 will turn on off the hobb switch

 

What gauge wire is currently running the 255?

 

Whatever comes with the buschur double pumper kit