Farmall M Noise: Governor or Manifold Leak?

Sorry for the odd title, but didn't know how to word it.

I was trying to smooth out my M, which was missing some and not responding very quickly when going from fast to slow idle, etc. I started checking timing with timing light (thought I was going crazy until I figured out that the engine was timed to #4 cylinder instead of #1).

At one point, while at low idle, the engine was starting to fall off (might have had timing retarded too much) when it kind of popped (loud noise) and the engine revved up some, accompanied by a whine/whistle noise. I shut down the engine, whine trails off as engine stops turning. Earlier I had sprayed some carb cleaner in the governor to clean gunk. Took off cover again and noticed that governor linkage was loose. Thought something had broken in there, but after checking linkage up to carb, etc., and moving throttle lever at steering wheel, tension returned to governor (no longer flopping in housing). Engine does change speed when moved from slow to fast, etc., but still doesn't want to drop down to low idle. Missing is still present.

So my question is, did my cleaning of governor remove lubrication enough to ruin bearing to cause whining noise? Or does the intake manifold have a suction leak that's producing the noise? It's hard to tell where the noise is coming from, except that it's from that side of the engine.

Any other tests to do to determine it? Sorry for the long post, just trying to get the tractor running right. Thanks for any help.

While its running, spray some carb cleaner or starting fluid up near the manifold gaskets,, if it smooths out or changes tone you have a vacuum leak. You might get away with tightening the bolts, or replacing the gaskets which ever you think is best. Chad

Thanks for the reply. Any risk of fire if spraying starter fluid close to the exhaust manifold like that? Obviously not trying to spray that manifold, but they are close together. Also, how much chance is there in breaking off a manifold bolt/stud if trying to check tightness or remove manifolds? I'm not going to really crank on them either way, but didn't know if they were notoriously weak to begin with.

There is always the risk of fire, but you should do this while its cold, just fire it up ideling, and spray it down where the head meets the manifold. if its a vacuum leak it should change sound by smoothing out a little. Id say if you do tighten the nuts on the manifold,,,, warm it up real good,, then try to turn em,,,, the heat should help them turn a little easier. Ive had to fix broken studs from this, not fun, but it could happen so be careful. Chad