I would take my time and brush off as much dirt as possable with a tooth brush, being sure not to get any dirt (or any more dirt ) into the carb...remove carb if necessary.
Then spray it off with automotive carb cleaner...leave the muffler on, or plug the exh. w/ paper towel...the "jet spray" will get rid of anything you missed with the tooth brush.
Q-tips come in real handy too...

Sometimes, soaking the engine will allow dirt that you might have missed to get into the engine and do more harm than good.

Only disassemble if it's abosolutely necessary.

Edit: I see that it's an LA...then carb cleaner might not be the best thing to use...it could damage the plastic backplate? If it's a blue one, it might not be friendly to that either?

If you rinse w/ water, make it rather warm/hot water, then test run it long enough to burn off any moisture and/or oil it throughly asap.

(I WAS gonna make a wise a** comment...something like..no matter how well you plant them, you'll never get a new one to sprout.....but I won't )