sewflynwa

Hi,

I am trying to determine what kind of OS .25 rear exhast engine I have, VF ABC or VF-DF ABC. There is no box or manuals, there is a V on the left side, 25 on the right, 2807 on the rear crankcase cover, KR on the bottom of the right side mounting points, and 2CB on the carb. I have not disassembled it to see if anything is stamped internally as the engine appears new and never run but can if necessary.

Hope this is enough info,

Thanks

C

Bax

My Feedback: (11)

The O.S. Max .25 VF-DF engine had the #2CB-D Carburetor. The .25 VF ABC engine had the #2CK carburetor. Your engine is likely the VF-DF version.

yank51

Take a look here to help you identify...
http://osengines.com/history/ostimeline01.html

sewflynwa

Yank51,

Thanks for the link. My engine is on the 1982 page. A close as I could look, I could see no external differences between the VF and the VF-DF engines. The carb numbers were too small to read however.

Cary

Bax

My Feedback: (11)

The differences between the regular VF and the VF-DF versions would be the intake and exhaust timing...the ducted-fan version was ported for much higher RPM with a tuned pipe.

Roguedog

I just got a OS Max 25 VF DF and heard that if you carefully take the backplate off and see if the letters DF are stamped in the counterbalance on the crankshaft, the engine is a 25 VFDF.

sewflynwa

Roguedog,

I finally broke down and pulled the engine's backplate to see what the real story was. Clearly stamped was 25DF on the crankshaft counterweight. This along with the 2CB on the carb is proof positive the engine is the 25 VFDF.

Thanks to all,

C