Having someone rebuild would be big bucks. Only way a rebuild makes sense money wise is to do it yourself. You would be very surprised how simple these carbed two stroke are. If you have a service manual and a little common sense, you can do it. I’ve rebuilt two motors now and both turned out great. Bought my last boat for $600 because the Johnson 140 had been overheated. Cost me $1300 to rebuild it, and now have a nice little boat. If you don’t want to take on a rebuild, then finding another powerhead is the way to go.