John Deere A carb on B

My dad and I are working on a 44 B that he bought that was stuck. We have it mostly done, ready to fire next couple of days. I started to go through the carb today and found it to be a dltx 71 which is from an A. The carb has some issues, the throttle butterfly does not fit the casting well and the choke shaft has been brazed in backwards and will be hard to get the screws out. I am gonna clean it up and try it. My question is will this thing run properly?

That's a hail Mary. Worth a shot but it will or won't.
Lol

I have a couple carbs for b jdz might sell tractor ready email is open.

Give me a call at 605 270 1844 will trade your 71 in for the right one for your B rebuilt and ready to go

It will run but may cause spark plug fouling issues. I bought a late B that had an A carb. on it. Previous owner got tired of it fouling plugs. With the proper carb. it was fine.
Take the deal for the swap !

Simple answer is Yes it will...just not certain THAT one ever will. Also, if you do run a large bore on a small manifold, you need to die grind the manifold to the stencil of the intake gasket and taper it back at least 3 " It needs port matched. The needles set the fuel to air ratio the engine needs, not the size of bore. Whatever air a given engine will ingest , you add fuel with needles until it is correct air-fuel ratio for perfect combustion.The fuel passages are same size on 67 and 71 as are the needles. Only diff is bore / venturi size and that just flows more air if engine calls for it. The load nozzle is different but it only gets what the load needle will give it. When I test a 67 or a 71 on my late "B", the needle settings for best operation are within 3 clicks of being the same. A carb does not force feed an engine, the engine takes only what it needs. Air : fuel ratio makes them run right.... the volume of this mixture decides how much HP it makes. If you think about it for a minute, a larger bore carb should make it run lean if anything because it has the potential to pass more air for a set amount of fuel...set by needles. I don't expect anyone to believe me but I test all sizes ea week on same tractor and the carb I use on that tractor when I want to plow/disc etc is my personal # 71 on a cold gas manifold tapered back. I won't go back to a 67, and I've had plenty I could have kept for it . One of the smartest men ever with these carbs was Robert Beaver built/operated Roberts Carb in Spencer , IA. Get hold of his video and see what he tested ALL carbs on and what he has to say about it. I've experienced the same thing in my shop with my test tractor , with 100,s of carbs from "H",s to "D",s and all in between. I don't claim to know everything but I do know what I see / hear right in front of me in my shop. Good luck on your carb whichever way you choose to go. I also have both 67 & 71,s for sale. Yours can be made right, just depends on how much you want to spend on it for correct parts etc. You need a #40 , # 53 and # 58 aircraft drill bits and know where to use them if you ever want it to be correct in operation. Most all need new throttle shaft , bushings and throttle disc. My e-mail is open (classic view) if you want even more build info.

It might run, but thats it, I agree with Robert. We tired running A carb on B tractor for pulling. Could get it started, only way it ran ok was full load on the dyno, and after about a day of screwing around on the dyno, we couldnt gain any hp. I dont recall the carb numbers.

After checking around, we picked up a carb from a local guy for $140. It does need a new needle and seat, but we were able to fire it up and drive around a bit. Found some noices that need to be fixed yet (fan shaft or governor and a bearing in the trans/rearend) glad to hear it run though.

Thanks TJ