schebler model H tips and advice!

[T. Cotten]

Tommo!

Not only am I entering a minefield, I'm blind and wearing lead snowshoes.

One aspect that always worries me is vacuum leaks.
How were these early manifold threads sealed?
Was there a gland nut to lock the carb upright?

....Cotten

[DanM]

butterfly angle?

Tommo- in your post of 4 3 you point out the 3 different angles on the butterfly. What angle does that refer to? Is it the edge of the disc relative to the face? What is the affect of mixing these up? I am using the same one I unsoldered from the shaft, but am cutious.

Also- the low speed screw. I'm rebuilding a HX 181. It did not have a low speed screw when I obtained the body. I bought both a repro and a NOS, both are the same length, and both are too short to seat against the notch by the throttle shaft by almost 1/4". I have reviewed different literature for the H and can't see when/if the screw was changed. Any advice in this area? I assume for idle the screw tip needs to be able to close the notch nearly fully? I can extend the tip, but would buy the longer if it is really out there.

Also, when the float valve ball is secured by the nut, should it have up and down play, or be like a heim ball joint- meaning pivot but not play?

Final question- when the bowl nut is on, there are few threads left for the hot air intake. How many threads are typically exposed below the bowlnut?

THANK YOU

[Tommo]

Dan,
The degree angle is the edge of the butterfly relative to the bore of the carb.
On 1 inch and smaller bore Model H carbs it can be either an 8 or 9 degree angle on the edge of the butterfly depending on the model.
The 1 1/8 to 1 3/16 bore carbs are usually 12 degrees and all the bigger bore ones 13 or 14 degrees once again depending on the model.
When fitting a butterfly to a Model H you require the butterfly to stop turning in the carb bore at EXACTLY the same time as the throttle stop on the cam track hits the stop on the carb body.
At no time ever, should you be able to rotate the butterfly through 360 degrees.
The butterfly when closed should fill the carb bore totally and be in the centre of the idle speed screw when at rest against the throttle stop.
I gave up trying to solder butterflys back in years ago and have for many years made replacement throttle shafts with screw holes and mount the butterfly using 2 #5 32 tpi screws. This method makes it so much easier to centralise the butterfly in the carb bore.
If there are butterfly chatter marks in the bore of the carb you will have all sorts of trouble in getting the carb to perform if you don't remove them

Your idle speed screw should be 31/32 of an inch long when measured from the underside of the hex head to the end of the screw.
It sounds like you have a 13/16 of an inch long idle screw that is for the smaller bore Model H's

The ball pivot for the float needle should have a very small amount of up and down movement. I can't tell you exactly how much as when I assemble them experience tells me if it's right or if it's too much. The needle should be free from any binding and wobble around freely. I always check this while the arm is out of the bowl.

Normally there's somewhere between 3/16 to 1/4 of an inch spare thread protruding below the bowl nut.
The bowl nut for a carb with an air horn fitted is 7/32 thick where-as those that were not intended to have one fitted had a thicker nut at 9/32 thick. An 1/8 of an inch makes a lot of difference in this instance.

Finally before anyone asks NO! I'm not doing any more carbs. Alan Travis caught me at a weak moment and I've done one for him to use on his bike in the Cannonball but that is the last, finish, no more, so please don't ask as my reply may offend you.

[T. Cotten]

Tommo!

I have no problem custom-cutting the different angles for the outside of the butterfly discs, as I made mandrels for most of them (attached). But to hand-file the angles to the idle screw is quite a chore!

Have you any information as to those different angles, and tips or tricks as to how to cut them?

We all greatly appreciate the experience that you pass on to us!

....Cotten

[DanM]

Thank you Tommo and Cotten

THANKS Tommo and Cotten for your guidance!

One last question- could you measure a bowl for the larger bore HX 181- for the height- the dimension that would set the threads of the stem showing. My bowl is 1.95" and is stamped DL4 on the gas inlet below the float pivot pin. Is this an H bowl? It did come with the lever and float valve with the ball....There are only a few threads showing beneath the nut. Although my nut is thicker, I made it from a Linkert bowl nut by turning off the bulge to keep just the nut, I can cut it down further.

[Tommo]

Cotton,
So long as the butterfly is a good fit in the bore the angle on the relief that the idle screw protrudes into is not too critical as when you adjust your idle speed the end of the screw has plenty of clearance. You do need to try and keep the clearance between the top shank of the screw and the top of the notch to a minimum. Around about 2 to 3 thou.
We always use a full circle butterfly and not the style with the flat top and stuffing washer as it is a lot easier to get a full seal and then have better idle speed control because you are only worrying about the space around the idle speed screw.
As far as cutting the relief we have made jigs that hold them so we can cut them in the mill. The only trouble with this is that you need a seperate jig for each of the main butterfly sizes and customers have trouble understanding just how much time and money is outlayed to be able to do the job properly. Because we screw mount the butterfly these two holes are critical to the whole operation as they are our datum points for all our machining operations and all our jigs are made to suit these two holes

Dan,
You have a Deluxe bowl which if I'm right should measure 1 15/16 high
The Model H bowl is 1 13/16 high.
The best way to tell the difference is to look at the bowl side on and you'll see that on the Deluxe bowl the surface above the needle valve that the small cap screws down onto is above the surface of the main bowl by about an 1/8 of an inch.
The model H bowl is flush right across both surfaces and the Model H bowl is straight sided at the top where-as the Deluxe curves in slightly at the top.
I only have a very basic digital camera and it doesn't take very clear close-up photos so I'm not able to post pictures that might explain things better.
Sorry about that.

[T. Cotten]

Dan!

Attached is a comparison of the two styles, with the larger version shown on a patinated HX181.
I do not even know which side of the carb the bowlvalve belongs!
The 'horseshoe' float seems to allow it to be anywhere.

And Tommo!
I use the two screw holes to index as well, as that it the only way my bevel mandrels can work... And of course I can then use DLX choke butterfly discs, or most often Linkert throttle discs for blanks. If you can find a 'macro' mode on your camera (usually a little flower comes up on the control display), I would really appreciate a clue as to your approach to the relief jigs.

The examples that I have encountered with no 'stuffing washer' had the shaft retained by a lip of the body casting rolled over it on top. How do you prevent upward movement and wear into the bore without the domed washer?

Again, many thanks!

....Cotten

[T. Cotten]

It has been brought to my attention that Type "A" DeLuXe models used the same bowl as the 1 1/4" HX models!

The '28 Service Station Manual pictures seem to confirm this, as well as the examples on my benches.

....Cotten

[Tom Lovejoy]

Thanks for sharing this info guys, good stuff to know and learn.

[marsh1915hd]

The beat up ones

Sometimes you find a carb that has been in the bottom of the rain barrel for years all the steel bolts are rusted to the point where you can't get them out. Here is how I get them out. Battey acid, drill a hole in the bolt as big as you can, then put the carb in acid for a week or more. All you have to do is run a tap in the hole and you are good to go.
One more good trick is freezing brass. If you have tryed to heat and bent brass you know it don't work but if you freeze it, it will bent like butter. Have fixed many parts with these tricks. Levers and carb ears are easy.
I has taken me years to learn these tricks, try it.

[T. Cotten]

Sometimes you find a carb that has been in the bottom of the rain barrel for years all the steel bolts are rusted to the point where you can't get them out. Here is how I get them out. Battey acid, drill a hole in the bolt as big as you can, then put the carb in acid for a week or more. All you have to do is run a tap in the hole and you are good to go.
One more good trick is freezing brass. If you have tryed to heat and bent brass you know it don't work but if you freeze it, it will bent like butter. Have fixed many parts with these tricks. Levers and carb ears are easy.
I has taken me years to learn these tricks, try it.

Wow, acid is a little rough on Miss Patina, isn't it?

I absolutely agree that heat is verboten when bending brass and bronze.

Attached is my hi-tech approach to bent H airhorns.

....Cotten
PS: Anyone needing a spare billiard ball, I've got freebies.
(But the 8s are all spoken for....)

[23JDCA 808]

. . . If you have tryed to heat and bent brass you know it don't work but if you freeze it, it will bent like butter. . . . .

Brass and bronze can contain air bubbles, which explode if you heat it with a torch. ...bill

[Tom Lovejoy]

Right on Cotten and Marsh, I never heard of either method and my airhorn is bent. Thanks again for sharing .