WD not running smooth

Here's what I have checked so far: 1) 82-85# compression on each cylinder (wd manual says 110 is standard); 2) valves checked for proper clearance; 3) new ign. wires with mag putting out spark at each plug; carb. overhauled and then replaced with a rebuilt one that was test run on another tractor.  The engine starts instantly and has good oil pressure, and it runs with no smoke or odd noises.

Would 85# compression instead of 110 cause the engine to run roughly or are there other things that I should check?

Thanks.
Neil

burned valves or worn seats would.

Compression variance is typically all cylinders should be within 10 percent of each other.....yours is low, but balanced.

When you say it's running 'rough'... do you mean that it misfires on random cylinders?  Does it drop one or two cylinders consistently?  Does it pop and crackle?

One of the things I've learned about these magneto ignition systems, is that ust because it appears to have good spark, doesn't assure that it's totally good.  A local feller here has his own magneto shop, and went through several of mine, all seeming to have good spark, but generally poor running result.  After he went through 'em, they all run solid-as-can-be.

Magnetos have ignition points and a condenser, just like battery-coil.  The points need to make good contact, and to do so, they need appropriate dwell, spring pressure, clean contacts, and proper phasing with the spinning armature.  THEN, they need strong enough magnetism in the frame, and finally, in order to generate a suitable firing pulse, they need a good condenser.  Any ONE of these items will cause you to have an unstable spark, or a spark event insufficient for lighting off a mixture in the chamber.

Last, but not least... your magneto has an impulser, which not only causes the armature to 'flip' fast on a low RPM start, it probably also retards the timing event past TDC for a safe and easy hand-start, and then... advances the spark when it's time to run.

I wouldn't discount the valve question, but before digging into the head, I'd certainly yank the mag and take it to someone who really knows mags well... what you're describing sounds like either the magneto is unstable at any speed.

""-Manifolds were recently reinstalled with new gaskets and red RTV, so I don't think they leak. "