? for GB or anyone who knows

L. B,

Member
I have finished my 46 2N and had to use one of my old ebay org carbs that I rebuilt. When I got it it had a copper tube and fitting where I put the brass cap on. Someone had drilled a hole right through the housing and through the venturi. Why and or what for,I replaced the venturi and capped the hole. Works fine.
a97695.jpg
 
Easy place to spray starting fluid in so that you do not have to pull the air cleaner tube
 
My 46 2N had a valve on a 1/4 nipple welded to the breather tube about midway. I took it off and capped it with no problems. A friend looked at it and said he thought it was there for a vacuum also.
 
(quoted from post at 11:54:29 01/22/13) I believe that was a vacuum hook up to use for milking, not positive though.

milking machine tap would have been on the manifold for best operation.
maybe someone was trying water injection?
 
Thanks old, I forgot to mention that it had about 6 ins. of 3/8 in. copper tubing with a flare nut for the flared fitting coming out of carb. They had just bent the tubing till it broke. So I dont know how much longer it was, maybe for spray?
 
LB,
Sounds like a "primer cup" opening, but those are usually tapped into the manifold. My R2 Cat has two brass primer cups on the intake manifold. Levered valves at the bottom of the cups allow fuel to enter the manifold and then closed before starting the engine. They are quite effective for speedier cold weather starts. Just a thought!
Mr. T. Minnesota
 
(quoted from post at 22:50:08 01/21/13) I have finished my 46 2N and had to use one of my old ebay org carbs that I rebuilt. When I got it it had a copper tube and fitting where I put the brass cap on. Someone had drilled a hole right through the housing and through the venturi. Why and or what for,I replaced the venturi and capped the hole. Works fine.
a97695.jpg
Someone sent Gary one with a plug in that location about 3 years ago. I do not recall anything being said about it being drilled all the way through into the venturi. If that were actually done, as described here, then the pressure balance of the carb would be terribly upset as the space surrounding the venturi (that is, space between cast wall with plug & the venturi) is normally at vent pressure (same as intake opening), whereas as the inside of venturi is lower pressure generated as a result if air flow through the venturi. If those were ported together as this suggest, then the carb would not function or would function so poorly that the tractor would be unusable. You can demonstrate this effect by installing the venturi upside down such that it will not seal at the ends, as has been done unintentionally by persons in the past. Makes no sense why anyone would drill all the way through into the venturi itself. Especially, leaving the vent to inside venturi connection. Are you sure there was not a tube sealing into the venturi & simply passing through the space between the wall & venturi? This would be a very different matter, as then the two different pressure areas would not be connected to one another.
 
I figure for starting fluid since that is right where the fluid would need to be to work the best. But one never knows for sure on something like that
 
(quoted from post at 08:35:10 01/22/13) Ive seen some one do something like that and switch to lp. Bob
t this point in time after looking carefully at the pictures of the one Gary has & discussing the exact location of the hole with him, I tend to believe badger Bob hit the target with a propane input. Details of inside/outside of Gary's show the hole not between top & bottom of venturi, as suggested by the comment about "drilling through the venturi", but rather above (air flow wise downstream of venturi) the venturi & below the throttle plate.
.....and if LB's did actually have tube into venturi for propane, it wouldn't matter about the vent & bowl pressures as it would using gasoline. Some propane carbs did squirt into the venturi (see FO-20)..
 

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