Farmall M Manifold Questions

Thanks
Tim

The crack in the intake manifold can indeed affect operation of both #3 and #4 cylinders since both share the same manifold runner. A leak there can cause symptoms somewhat consistant with what you describe. And there's no point in messing further with the carburetor until the leak is eliminated.

If you can get at the cracked area you might try temporarily patching it by wrapping with electrical tape, or by buttering it with silicone gasket maker or JB Weld to verify that's the problem.

Thanks for the comments -- I should have figured the M's manifold would be longer. I can get to the crack and if JB weld or some such would hold long enough it would be good to verify that its the primary problem.

What do you know about welding the manifold -- I have brazed some cast iron before and they make electric arc welding rods for cast iron? Don't know what polarity is best for welding on cast or how well the electric arc rods work?

Thanks again

Welding cast iron is kinda fussy, but there's welders out there who are pretty good at it (I'm not one of 'em!). It also may be possible to braze the crack shut. You might post you welding question over on Tool Talk - there's couple regulars there who know their welding stuff.

Worst case scenario is to simply buy a new manifold. Last M manifold I got was $130 or so.