Externally this is the difference....

The 140L has this big round mounting lug on the rear of the carb.

140FZ does NOT have this big round lug.

Internally there are a couple differences.

All the 140 and bigger engines (also the 120FZ) after the 140L was introduced have this big round mounting lug on the rear of the carburetor. A photo of it is below.

So if you have a 140 with the Lug on the back of the engine it is either a 140L or 140 Sport. The difference between these two is the rear crankcase pressure line hook up the 140L has it and the 140Sport just comes off the regulator like the earlier YS engines.

If you notice in those photos the rear of the carb is missing this big round lug, yet the pressure line looks like it goes from the regulator to the backplate. This means its a 140FZ in the photo with the airplane.


The below photo of the rear mounting lug is froma 140DZ or 160DZ not the 140L but the 140L has the same mounting lug.

Motors that have this feature are since 1999 and include:

140L
120FZ
140 Sport
140DZ
160DZ
170DZ

This mounting lug attaches to a special vibration damping engine mount sold by YS. Its designed special for Competiion F3A pattern planes. This mount was introduced with the 140L in the 1998-1999. All of the "Pattern" engines built since then have had this round nub on the rear of the carb. Eailer engines like the 140FZ circa 1996-1997 and before don't have it.


Oh one other note....look at the needle valve in the far right photo....its the newer style. That needle valve did not come on the 120SC and was intoduced with the 140FZ. SO that engine is a 140FZ. I would bet my new 170 on it. Its a 140FZ for sure.

The needle valves from the older 120's was a big silver handle not the smaller diameter gray colored one.

Troy Newman
Team YS