Linkert M-51 help

[khochstein]

1947 WL

Linkert M-51

Starts great runs great!

Cant get idle to slow down, butterfly closed tight, idle screw backed out.

Butterfly fits tight
bushings good

If I have an intake leak wouild it speed up or slow down?

Small hole and slot on right side of venturi, I assume is to let some air bypass when butterfly is closed. There is a plug behind this slot from the outside, is there some kind of adjustment or is it just a plug? can this slot become worn too big?

Any ideas guys?

Thanks for any suggestions

[Sargehere]

An intake leak would lean it, and probably keep it from idling down. That's easy enuf to check: put some water in the ol' lady's "Fantastic" squirt bottle, and squirt the intake joints with it running. Should (not) get a reaction, unless there's an air leak. Cotten, on this forum, is the Linkert guru for most things. He's probably on his way to Davenport, or soon will be.
The air bleed is a tiny slot in the barrel of the carb where the butterfly meets the wall, and is usually non-adjustable. It sounds like either an air leak or an adjustment 2me.

Butterfly fits tight...

The butterfly is in with the bevel in the right direction, edges flat upon the inside wall of the barrel, isn't it? We have had people put them in backwards, sharp edge to wall, and complain of not being able to idle down. Just dbl checking.

[khochstein]

Yes I have the bevel correct so it seals tight.

I will test for intake leak but I always thought it would slow the engine down not up

I will post results

Thanks

[T. Cotten]

Khochstein!

No two vacuum leaks behave the same, except those that prevent the machine from running at all.

To determine if you have a leak, as well as exactly where and how much,
please pressuretest your manifold assembly as discussed at http://virtualindian.org/11techleaktest.html.

The tiniest fissures will display themselves as little blisters of foam after a minute or so; No leakage is acceptible.

One interface that cannot be addressed by testing is the junction of the carb and manifold flanges.
The manifold's flange should be arbitrarily ground to flat, and the carburetor flange lathe-cut true. The point of leakage is commonly at the idle gallery plug, as shown in the attachment. Fat and spongy gaskets contribute to this problem.

Once this variable has been eliminated, we can go on to concerns within the carburetor itself, such as excessive borewear, shrunken venturi, etc.

Air enters the front idle bleed hole to mix with fuel and air within the idle bleed well before exiting the rear hole; The slot somehow improves the off-idle transition.
There is no provision for adjustment for the well in Model M Linkerts (unless tossing an Indian 'titted' plug into it would have an effect.)

Good luck!

....Cotten