Carb Question

[Mr. Big]

Curious about these drilled and soldered stems I'm finding on '39 and earlier M51's and M5's. I have yet to come across an L&L M51 that has the stem drilled and soldered. I noticed that all I've seen are milled and pinned for an inline bowl whether they are stamped M5 or M51 which I assume is just the way they were made. The drilled and soldered part has me stumped. Did they come from the factory this way, or was this done later as a repair procedure for some reason?

M51


M51


M5

[T. Cotten]

Mr. Big!

That's the way they were made, and other models as well, although the assemblies were at great variance from the display of parts in your last picture.

There is quite a spread of years represented, and some modern imposters as well.
And nearly all finishes have been destroyed entirely, or are the wrong choice for a pre-War model, or any model for that matter.

Please do not put it together like that unless it is a pure custom that shall sit on display:
If that is a 9 gm float, it might as well be a brass boatanchor float.

I apologize for being so frank and candid, its just the way I am compelled to reply.

...Cotten

[Mr. Big]

Thanks, Mr. Cotten. None are mine except for the middle M51. Just completed my first rebuild of another M51 that I swapped out tonight and plan to fire up tomorrow. Since I'm a total newbie, I hope it goes well! I am facinated with these little carbs and I've been trying to learn as much as I can about them.

By the way, do you know why those early carbs were made that way and the later ones were not?

[T. Cotten]

Mr. Big!

I have been trying to learn as well.

All manufacturing procedures evolve, although Linkert's introduction of welch plugs was not their finest innovation.
I would imagine perhaps they tended to leak, or the soldering process was just too messy.
They soon returned to the original Schebler design, and even incorporated Schebler's fixed jet idea.

....Cotten

[Mr. Big]

Hey, thanks so much for the info, Mr. Cotten. Mystery solved and others to come.....


Oops, one more question. What was the purpose of the "welsh plugs"?

[T. Cotten]

Mr. Big!

The welch plugs require less meat than a threaded plug, or were just cheaper, I would suppose.
Why the galleries were drilled all the way through, instead of blind like later models, is a mystery to me as well.

They still used plugs on the opposite side, where there was more casting.

(My previous posting was a bit misleading, as Schebler plugged from that side, rather than the opposite.)

....Cotten