I recently purchased several older FSR series OS engines and have noticed they have a brass fitting screwed into the side of the muffler(not the pressure tap nipple) opposite the egine exhaust inlet. This fitting is a hollow tube about .75 inches long that projects into the muffler. Anybody know/remember what this fitting is for ?

It was for priming the engine with some kind of needle. I have never seen the apparatus
used to prime the engines though.

FBD.

Thanks, makes sense i guess

The special apparatus used to be the plastic squeeze bottle we used to fill the tanks before electric pumps came into vogue although I suppose a small syringe could have done the same job. Enya mufflers have a rotating plate on the side to do the same thing. Not that anyone ever uses them.

My enya CX11D has a nipple also on the top of the manifold part of the muffler besides the one in the muffler the 25D does not ,just the one in the muffler and the 11 starts fine with the usual finger over the carb prime maybe a left over from the glow enya 11 same muffler wich has been around for years martin