Tiger, your engine's manufacture date was 25 October, 1985, and it was made in Briggs' Poplar Bluff, Missouri, engine plant.
The VacuJet carburetor was a cheaper alternative to the more complicated PulsaJet. The difference was that the VacuJet used carburetor venturi suction to suck fuel up from the fuel tank, through the main jet, to the discharge nozzles. The PulsaJet had a fuel pump which continuously pumped fuel up to a small secondary fuel tank in the top of the main fuel tank, allowing the secondary tank to overflow continuously. Venturi vacuum just had to suck the fuel up the very small, and precisely constant, distance from the top of the secondary tank to the discharge nozzles. This made the air/fuel ratio considerably more consistent in the PulsaJet. In practice the VacuJet is rather unsatisfactory in the deep fuel tanks used on horizontal crankshaft engines, but it was not really an issue with the shallow tanks on the vertical crankshaft engines.
The downside of the PulsaJet on vertical crankshaft engines is that its fuel pump diaphragm (including the pump's flap valves) is sandwiched between the fuel tank and carburetor, instead of just having a gasket there as the VacuJet does. This means the vertical crankshaft PulsaJet requires more care in assembly to the tank, than the VacuJet does. In the case of the 92000 series engines, which had automatic chokes, the PulsaJet's diaphragm had to be pre-loaded when assembling the fuel tank to the carburetor, and this requirement has been the downfall of many mower repair shops which failed to do it, thus preventing the choke from working and the mower from starting. Some of the unsuccessful mechanics then waged a public relations war against both PulsaJet and VacuJet, recommending use of the PulsaPrime.
The VacuJet is considerably easier to work on than the PulsaJet, but I suggest you should read the Briggs manual and follow its instructions.
So far as removing the carburetor and fuel tank, as an assembly, from the engine is concerned, the process is much the same for PulsaJet or VacuJet - the governor link is a bit of a pain for both, but it's nothing major. The rubber breather elbow looks the same for both but it isn't, you need to use the correct one or it won't fit properly.
