Re: 1973 Johnson 50hp esL, Can't get carbs back on block bolts??
Puzzled here.... what bolts?
The carburetor slips over fout (4) threaded studs and is retained by four (4) nuts. The bottom nuts must be threaded on first. If you thread on the top nuts first, there will not be enough clearance left to start the bottom nuts on the bottom stud threads.
If you indeed have bolts instead of the threaded studs and nuts, that's someone's idea of a "upgrade". If this is the case, gradually start all four bolts before tightening any of them. Remove the carburetor(s), look every one of those bolts over to make sure they all have the same thread, then with the carburetors set aside, install every one of the bolts first to make sure that the bolt to threaded intake manifold match is perfect.