swaped engines in tractor, now it won't start

[crazyoldtractor]

I swapped the engine in my lawn tractor and now it will only run when I pour gas directly into the carburetor. The old engine was junky so I put this other b&s OHV in it.

Extra info:

New engine currently in mower: craftsman OHV B&S model: 28N707, type: 0162-01, code: 9503314A
Old engine that is no longer installed: craftsman B&S model: 252707, type: 0621-03, code: 36040111
Tractor the new engine is installed in: craftsman model no: 917 255736, serial: 0976S13535
Tractor the new engine came out of: craftsman model no: 917.252531, serial: i cant read it.
Also the new OHV engine ran just fine before I installed it in the new tractor. I just dont get what is different now?

If someone can guide me as to what is wrong that would be great.

 

[noma]

Hi Crazyoldtractor

Just wondering if your old engine had a solenoid on the carburettor ,was there a wire to the carburettor on your old engine? If so does your new engine have a solenoid on the carburettor and a wire going from there. This might be your problem it's not letting gas into the carburettor. You need to hook it up or by pass it in your electrical wiring.:smile:

 

[crazyoldtractor]

Actually the the new OHV engine has a wire comming off the carb. I dont know much about how it works. I connected it. Does it need to be connected to 12v or something to work right?