Farmall 130 still having a miss.

With the help from many of the members of the forum I was able to get my 130 running but still cannot find the cause of the miss.I have checked everything I could think of and was suggested but no joy.Tried 2 sets of new plugs.Checked plug wires.They seemed OK.In fact until this started it ran like a champ.I did a compression test.2cylinders were 125 one 115 and one 110.I don't know what the optimum is supposed to be.The coil had a fairly good orange spark but not blue.None of the plug wires had a blue spark either.Do I need a hotter coil?I had put on new points and condersor.Checked wires and resister for continuity.One thing though.Every time I started and ran the engine even a few minutes the plugs were sooty.I tried to lean the carb but no main jet adjustment or air adj. just idle adj.and throttle adjustment.Don't know what else to do and need advise.I'm having to pay someone to mow large yard.Thanks for any help.Charlie

Please post a couple pics of the carb.

I don't remember what all was covered before, but...

Revisit the points. Check the distributor shaft for side play. If there is any wear the points will not stay set. They can do some strange things, close up at different RPM, overheat and burn. Points are a pain when everything is right, if not right they will die prematurely. Try an old condenser. Chances are the coil is good. A hotter coil will not be of any benefit except to the place selling it.

The compression is not perfect, but should at least fire on all cylinders. Did you check the valve lash and inspect the valve train? Check for broken springs, bent pushrod, rocker not moving or not as much as the others.

When it is running, what does the exhaust look and smell like?

Black smoke is too rich. A puff of black on acceleration is normal, but it should not sit there and chug black. Does the carb drip sitting with the fuel on, engine off? Will the idle mixture adjust? It must be idling slow, 400-500 RPM for the idle screw to have any effect. Most of the updrafts, turning the idle screw in richens it, out leans it. It adjusts air bleed, and has minimal adjustment capability. But if it has no effect, something is clogged or there is a vacuum leak, or it's trying to flood.

Eye burning, raw gas smell is a sign of dead cylinder misfire, for whatever reason, usually spark or compression.

Vacuum leaks. Check the manifold gaskets. Is that a siamese manifold? As in the exhaust is cast together or bolted to the intake? Sometimes they can burn through, have exhaust entering the intake internally. About the only way to know is take the manifold off, lay it ports up, carefully fill the exhaust with water, see if it runs out the intake.

There it is... The most common things, but there always has to be something strange. One thing for sure, it will be the last thing you try!

Is it a dead miss or sporadic? With
engine running just above idle, pull
plug wires off of plugs one at a time.
If cylinder is firing you will hear a
new miss. If firing, put it back on
and check another unil able to
determine which cylinder is the
culprit. Then you know what cylinder
to to look at in depth. Wire, plug,
push rod, rocker and rocker action,
etc... if not a steady miss but seems
to move around, look for vacuum leaks
worn distributor and other mentioned
things. Oh, may want to use insulated
handle pliers to pull plug wires.

not familiar with those engines, but my 860 ford was doing about the same thing. turns out the distributer mechanical advance wasn't
advancing as the area in distributor below breaker plate was pretty well packed with hay, dirt, etc. easy enough to check with a timing light
i'd guess. good luck

When you pull plug wires when it is running, it will bite you with about 7000 volts or more. use a pair of pliers with insulated handles, or a
plug wire pliers (special type non conducting) pull one at a time. if it slows down and misses more put it back on. If no change, it it that
cylinder. Looking at the distributor cap from the rear looking forward, the wires are placed clockwise around the cap. Usually starting at 1:30
(o'clock) for #1, then #3, then #4, Then #2.
The engine must be operated for 10 minutes before the plugs will be at operating temperature, and the operation will clean the soot off.
Make sure the cam on the distributor shaft is opening the points completely when you set them at .020" To get the distributor shaft so the
points are on that cam lobe, you must turn the engine by hand. This is because a 4 cylinder will stop with the points closed. Jim

I agree with showcrop. A pic of the carb would be nice. I have never seen
a carb on an offset Farmall that did not have an idle or air/fuel mixture
adjustment.

Sorry should have only said no air/fuel adjustment.

I recall working on a MM that had a miss and the problem turned out to be a chunk burnt out of an exhaust valve seat.