Can also try heat from a torch. All that said, may have to buy one if it is damaged upon removal.
I had to replace the carburetor studs on a V8 manifold. They wouldn't budge. Hit them with penetrating oil every day for a few days. Then one morning I checked, expecting some superhuman twisting would maybe get them off. They were finger tight! Like the good cooks always say, "Time is an ingredient" as well.
LawnBoy mowers are maneuverable and light, one reason is because they don't have a bunch of extraneous BS on them, and a cast magnesium deck, a very strong yet lightweight material. Many mowers today are "self-propelled". But, that's only because they have to be! They are WAY too heavy otherwise, and the self-propulsion adds yet even more weight and expense and complexity.
Next, LawnBoy mowers were very powerful for their size/weight, and not immediately apparent based on HP figures, this is their "ace in the hole" in my opinion, the classic four stroke B&S equipped contemporary mower that your goofy neighbor had, always noticeably labored in thick, tall or wet grass. Remember that? Probably even stalled out. RPM drops, and the quality of the cut suffered. Throw in a dull blade especially, and clumping of the grass clippings results. Unsightly, and leaves streaks. A well tuned LawnBoy doesn't even blink. No, we're not supposed to cut tall, thick, wet grass. But guess what? Sometimes ya gotta do what ya gotta do. And the LawnBoy will do it without complaint. I'm not recommending it, but It is obvious that the design engineers actually used the LawnBoy products extensively in real world testing and their products reflected that.
They were precision engineered and designed to run at 3200 RPM or better. This is very important to check when setting up the governor assembly. Make sure the engine is not running too slow. A small engine tachometer is inexpensive.
Take the time first though, to setup the rotating assembly itself for balance and trueness. Shims of various thickness are used to ensure the rotating plane is registered correctly with respect to the deck, and the blade itself is installed or "clocked" a certain way with respect to the crankshaft position. Make sure the blade too is checked for balance, is sharp, nor bent. New blades are not sharpened, believe it or not.
All of this effort is designed towards the aim of preventing power robbing RPM loss due to excessive vibration, caused by unwanted resonances due to an out of balance condition. This will degrade the quality of the cut noticeably, and this yet another feature of LawnBoy mowers. They simply made your yard look nicer than competitors products. And, reduced vibration levels also reduces fatigue on the part of the user as well. You can tell when they are running right, the engine will be a little staccatto sounding unloaded but as soon as you hit the tall grass it settles into the smooth "Lawnboy Hum".
The chute and blade design also makes them excellent for mulching leaves into the bag in the fall. Who needs a rake? Again mulching is where maintaining proper blade RPM comes in. As far as blade stiffeners go, think they did away with them at one point, I wouldn't worry about it.
