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How to Identify a Straight Through NH carb?

Posted: Wed Feb 20, 2019 11:03 pm
by Fozz71
Can anyone help me identify an NH carburetor and what is the way to ID a straight through carb?

Is it as simple as being able to see through it? Or are there salient features from the side to look for?

Thanks,
Jim

Re: How to Identify a Straight Through NH carb?

Posted: Wed Feb 20, 2019 11:09 pm
by Scott_Conger
Straight through on left for both pictures:

Re: How to Identify a Straight Through NH carb?

Posted: Thu Feb 21, 2019 10:23 am
by tom_strickling
What extra considerations if any are there for rebuilding a straight through ?

Re: How to Identify a Straight Through NH carb?

Posted: Thu Feb 21, 2019 10:35 am
by Mark Osterman
None really .... all the same parts. Just make sure all the little chambers are clean and plugged properly.

Re: How to Identify a Straight Through NH carb?

Posted: Thu Feb 21, 2019 10:36 am
by Scott_Conger
They rebuild just like any other NH...no different parts or adjustment.

My opinion is that they will perform only slightly better than the more common sway-back NH, often with slightly harder starting and a greater propensity to spit a little fuel when starting and sometimes when shutting down. Not always, but many people report this. I ran one for awhile on our '13 and believe it was a little harder to start. On a car with a starter, this may be less noticeable.

Re: How to Identify a Straight Through NH carb?

Posted: Thu Feb 21, 2019 7:53 pm
by Fozz71
Well I guess I am selling mine on eBay, I didn't realize it was a straight through NH. If you want a nice solid complete one- take a peek.

Thanks for the help ID'ing them, I had no idea how to tell them apart.

Re: How to Identify a Straight Through NH carb?

Posted: Thu Feb 21, 2019 8:59 pm
by Pep C Strebeck
The one that you have listed on Ebay is not an NH, a straight-thru carburetor yes, but not an NH and not made by Holley. Either a Western Auto or Simmons Super-Power, both aftermarket. There would have been a wire heating element where the brass screw is filling in the hole. Does the carburetor that you have in the listing have the small pot metal flapper in it?
IMG_5139.JPG
IMG_5141.JPG

Re: How to Identify a Straight Through NH carb?

Posted: Fri Feb 22, 2019 9:39 pm
by Fozz71
Where would this pot metal flapper be located at? Both butterflys are the standard steel and brass type so potmetal is gone, no wire has survived.

Re: How to Identify a Straight Through NH carb?

Posted: Fri Feb 22, 2019 10:24 pm
by Pep C Strebeck
The flapper would be located behind the choke butterfly and would mount/pivot on the small rod attached to the brass screw that can be seen in the photo below:
IMG_5130.JPG

You can see the small rod (horizontal) in this photo. This would normally be behind the choke butterfly but that has been removed in this photo.
IMG_5136.JPG

The flapper is supposed to help with low speed idle and make the carburetor run/operate smoother.