Welcome aboard to the greatest site I've found. I have a few 1655's. You should post some pics of yours. As for solenoids, I just get mine from an auto parts store. Not sure of a part #, but it's one from a 80's and 90's ford vehicle. Hope this helps you out.
I use a generic lawn and garden one from my Ace hardware store. Think it comes from parts tree or similar type place. I can also get same kind at local auto parts store, looks like same one. Couple diff ways to hook it up. some need ground wire which it comes with, and others don't. Instructions in the kit. I've been getting these for my Speedex tractors with Briggs, even tho they didn't have one when built and put all the battery power thru the key switch. They don't last and smoke comes out of them and they quit working. Too much current to put thru a key switch, so I change to the selinoid and diff key switch then.
Thanks again guys! I went with the Ford type solenoid from High Energy (China) part number SS-598. I'm not sure if it's OEM which was what I was after but it is exactly like the one that came out of the 1655.
Update on my solenoid replacement. I loosely installed the first one, everything worked well. I then tightened everything down and the last connection I had to make was to hook the positive cable from the solenoid to the positive post on the battery. Wouldn't you know the solenoid cracked and the post fell right off!
Had the wife stop on the way and grab another of the same and installed it. Turned the key and nothing! I double, then triple checked everything. I got the test light out and then the multimeter...determined the solenoid was bad. I removed the solenoid from the tractor and bench tested it, sure enough...JUNK!!!
Tomorrow morning I am taking a 40 year old solenoid off of one of my 8N parts tractors, I'll probably have better luck than this new China crap.