early o.s 4 stroke pumped engines
 

i just got a early model new o.s pumped 120 4-stroke, can some one please expalin to me the set up on this engine as there are no manuals for it anymore accoring to hobbico,i'm not to sure how to set up my fuel lines from tank to engine,on the back of the pump there are 2 fittings, one says ''in'' the other says ''return'',i understand that the in should be from tank to engine and the return gose back to the tank.the engine is is a cowl so how is the best way to hook up so i can fill and empty the tank becuse both lines from tank will always be hooked up to pump and there is now pressure fitting in the mufler, i could use the 3rd line in the tank to fill it but how will i know whens its full?,also any recomendations on a prop size,i ran the engine some on a test stand and while it is running you can see fuel constantly getting pumped back to the tank from the return line ,thank you guys for any info u can supply to me about this engine

RE: early o.s 4 stroke pumped engines
 

The easy way would be to use a three line set-up....the third line being the
tank vent line used as the over-flow line. The return line to the tank would
be used as the filler line to the tank....either with a fuel dot, or a remote
fueler. ;)

FBD. :D