NH Carburetor Floats

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Model T Ford Forum: Forum 2017: NH Carburetor Floats
Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Miller, Mostly in Dearborn on Friday, November 03, 2017 - 06:16 am:

I figured I would share two photos since I had two of my carburetors on the bench at the same time.





These are both 1926 NH carburetor floats. The shiny new float on the right is going into my Fordor. The other float came out of my Runabout. When Ford moved the tank into the cowl, the float was changed to a larger more buoyant float due to the increased pressure from the high mounted tank.

The Service Letters advised the dealers not to put the tall float into cars with frame mounted tanks. Since I am one who has run out of gas on an incline before, I'm thinking this larger float would decrease the amount of fuel in the bowl. As far as I know, our parts suppliers only offer the early version of these floats.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Friday, November 03, 2017 - 09:38 am:

I'll be working on a few NH carbs, so this is good to know.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Friday, November 03, 2017 - 09:46 am:

Iíd like to see that service bulletin... A thicker float would effectively lower the fuel level in the carb. Itís my experience that a slightly too high or too low fuel level (float setting) in the carb is noticeable in an otherwise properly rebuilt carb.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Miller, Mostly in Dearborn on Friday, November 03, 2017 - 09:59 am:

Adam,

Per your request.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry & Sharon Miller, Westminster, CO on Friday, November 03, 2017 - 10:41 am:

In doing a little research on these floats, I have found:

T-6201 (original smaller float) can be purchased several places, can be replaced with Briggs & Stratton #298514 or #692265, OR Oregon #49-362.

T-6333-B seems to have been a Ford only item dating from late 1926 and I have NOT been able to find a current, new item, vendor.

I hope this helps out.

Cheers,
Terry


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Friday, November 03, 2017 - 11:10 am:

I just spent some time looking thru 1925 thru 1927 service bulletins and didnít see that. Which bulletin year, volume, page did that come from?

I do think the larger of the two floats pictured is a completely different animal, and maybe not the T-633-b.

Tom, I would be very interested to see the prints for both the redesigned, and prior floats. Any chance on getting them sometime? If Iím thinking of the right person, you get over to the Benson Ford on occasion?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Strickling on Friday, November 03, 2017 - 11:21 am:

Thanks Terry. Quite a price difference.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Miller, Mostly in Dearborn on Friday, November 03, 2017 - 11:26 am:

Adam,

I have at least two NH carbs in my shop that have swivel needles and identical taller floats. I also have a Vaporizer on the shelf but haven't torn into it yet.

The snapshot is from the documentation letters by Year from Bruce's CD. It's under the 1926 heading. Yes, I do get to the Benson Ford on occasion but lately it's been harder to find time to do so.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Longbranch,WA on Friday, November 03, 2017 - 01:15 pm:

I've removed the taller profile floats out of Vaporizers.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Osterman on Friday, November 03, 2017 - 01:23 pm:

Just try to find a bowl for a straight through NH. These are offset drains and have a flatter bottom than the typical NH central drain bowl. I've had two sent to me to rebuilt a straight through ... and neither of them were correct. Still looking.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry & Sharon Miller, Westminster, CO on Friday, November 03, 2017 - 01:59 pm:

http://www.mtfca.com/encyclo/doc26.htm Scroll down to Nov. 16 for the info on T-633-B replacement.

Tom,

You're welcome. Always nice to get the parts you need at a great price and save a few dollars for more parts.

Terry


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Friday, November 03, 2017 - 02:21 pm:

Iíve rebuilt somewhere between 50 & 100 Holley NHís and Iíve seen a larger float like that On several occasions. I have a suspicion it is something that was ďpretty close and readily availableĒ at a time decades ago when T parts were scarce.

Each time, the customer had a mixture control issue and the float height was causing the issue. The taller float makes the fuel level in the bowl too low. With a low or high fuel level, your mixture will not be the same at idle as it is at 25 mph. With a low fuel level in the bowl, you can adjust your mixture for good idle but will be too lean to run good at speed.

Here is a picture of a ďtallĒ float that was causing problems in a Ford F carburetor (early Holley NH) I rebuilt earlier this year.



A more buoyant float would have to be wider not taller in order to exert more force on the inlet needle without changing the fuel level in the bowl relative to the top of the float which is where the height was always set from. Ford never varied their directions for setting NH floats AND the Holley Vaporizer float was the same.

Iím not saying your wrong. Iím saying Iím real skeptical that the taller float shown in the photos is the improved float mentioned in the letter to branches...


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Gelfer, Milwaukee WI on Friday, November 03, 2017 - 02:46 pm:

Adam, your float looks way taller than the one in Tom's photo. Yours is probably "pretty close" but no cigar, while Tom's may be the Ford tall float. It might me an optical illusion. Blue prints sure would help in figuring this out.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Friday, November 03, 2017 - 04:46 pm:

Very interesting thread! Makes me wonder a couple things,....

First, I have to wonder if this issue has ever come up on the forum before, as it seems to me like a very critical issue in carburetor rebuilding, on what has to probably be the most commonly used Model T carburetor.

Second, I'm wondering if maybe there are two very experienced carburetor guys whose "input" here would be important,.....Stan Howe and Russ Potter.

So where are you two guys when we need ya'....???


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Friday, November 03, 2017 - 05:24 pm:

My thinking is that the issue they solved in late 1926 by making a larger float was more a 1920's problem, since it was customers that drove on washboard roads that could get excessive gas consumption. By the autumn of 1926 when the new float was introduced most new T's had already had cowl tanks for a year, so it couldn't have been a very common problem since most roads were unpaved back then.

Today we mostly drive on much better roads, so I'd say it's likely the usual float is sufficient for most regular use even with a cowl tank - if the valve is properly ground and fitted (that's another issue with current repro parts)

If someone is determined to be absolutely authentic even inside the carb, then it's probably possible to find a used float of the larger model.

By the way - 1927 model year started in August 1926 and by then all cars got Vaporizers, so no more NH's.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Miller, Mostly in Dearborn on Monday, November 06, 2017 - 07:29 am:

Over the weekend I took my other carb and attempted to duplicate Adam's photo. This float appears to be somewhat different than the one he found in the Ford F carburetor.



Also here is the flat bottom bowl that Mark Osterman mentioned.



I also looked around for my vaporizer but have yet to figure out what box I put it in.


Top of pagePrevious messageNext messageBottom of page Link to this message  By ROBERT BERGSTADT on Monday, November 06, 2017 - 09:36 am:

The thick one is vaporizer
Bob


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Miller, Mostly in Dearborn on Monday, November 06, 2017 - 09:54 am:

I dunno Bob. I haven't opened my vaporizer yet to see what's in it. The two floats I show came out of NH carbs and the service letter seems to support their use in NH carbs if the customers complained. Whether Ford put them into NHs new is still to be determined.

I put this on the forum just to see if others are finding them in their carburetors. I'm guessing they should show up in the '26 NH more often because the dealers would have had them on hand.


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