Carburetor mystery

topchop

topchop

Senior Member
Carburetor - Holley Model 59 AA-1
Car – 1947 V8
Symptoms were stumbling when accelerating, either cold or hot.
Just rebuilt the carb with a MAC’s carb rebuild kit.
Runs wonderful. Not used to having no delay when mashing the pedal...


Here’s my question.
There is a #6-32 tapped hole in the Bowl cover. It looks like a piece of gasket material was used as a seal. (See pics). Does not appear in the instruction sheet. I did not install it. Should it be there?
 

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Small holes drilled in lids above the float bowl are usually from disused petrol fired heater take-offs.

As the take-off isn't there anymore the screw is plugging the hole.
 
Almost 60 years ago I drilled a hole there-abouts' for a gas-fired heater I installed. Boy those things really put-out HOT air, and before the engine ever warmed up.
 
No matter what the hole was for, it should be plugged. If not, it will allow abrasives to enter your engine.
 
Thanks to all for input. Plugged or not, no noticeable change in performance.
Common sense tells me to take your advice and plug it to keep any crap from getting into the bowl area.

Just curious, what exactly is a gas fired heater (in this situation), and how does/did it work? Heater for the motor, or interior area?

As always, new stuff to learn!
 
Topchop

There was an accessory gasoline fed heater for 1930's-1940's vehicles that fit under the dashboard, called Southwind, Stewart-Werner. The fuel was delivered to the heater from the carburetor float bowl to the heater by a small tube.

They were VERY warm, there was a real fire burning in the back of the heater. You can find them on ePay under "Southwind heaters, for information.
 
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If you keep your eyes open you should be able to pick up a similar carb for a few bucks. If you can snag one with a good top you could swap it over.

Mart.
 
If you do not like the screw a drop of J-B weld & smoothed over & I doubt you would even notice it. if you do give it a touch (Q tip )of aluminum paint.
 
Top chop, Did you read Oldskool's post? "Stumbles on acceleration." That is why they put an accelerator pump in the carbs. Forget about that hole and try Oldskool's post. Then post the results and we can take the next step. Oh, how some threads get off topic.
John
 
Oldford2 he said it ran great after he rebuilt the carb.
Question he had was what the hole was for?
 
On what it was for...hard to be certain of precise location without a slightly wider shot, but I think it is probably right above the little angled nook between accel pump bore and the straight part of the rear wall of bowl.
This would be a sensible place to put the tube (I think they are about 1/8" tubing) that would feed a Southwind heater. It would be well placed to avoid interference with the float. It would have been just a hole originally, and was presumably threaded as an easy way to plug it when the carb went to a new home.
 
OK, here is the result of the carb rebuild.
I used the power valve that was included in the rebuild kit from MAC'S. It looked completely different than the one I took out. I should have taken pics of both side-by side, but the new one was 1/4 inch longer than the old.
Whoever rebuilt it before me left me a nice burr on the jet screwdriver slot. Got new #51 jets from Summitt. When cleaning parts, noticed that the pump discharge nozzle had one side plugged, which means only one barrel getting fuel (or so it seems). Also, there was the usual debris in the bowl.

After setting the float, and checking the ball check circuit, setting the idle jet 1 and 1/2 turns out, the puppy started right up. A few adjustments later, on the road again. After a couple of days driving, I plugged that "hole" and didn't seem to make any difference.

Did some research on the heaters that you guys suggested. Thanks for all the great comments.
 
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