Just some general info to kick around:
If it is idling and tuning good you might think about just leaving the carb as is for awhile and check other things like the 4 jug nuts, do the tip sideways tests to see if idling changes which indicates maybe seals leaking (especially the clutch side seal) which if changing the chain tension causes idling changes is another indicator of the clutch side seal dried out and as lostone says about the decomp valve always leaks when trying to do a pressure vac test, but it will not bother the actual running and starting. After you think it's running good eventually pull the flywheel and check them 3 phillips head type block screws.
I got some of them saws, one I bought new back in about 1974 area and it's still a good runner and only one carb kit and a few new chains is all it's ever needed.. Storing in a hot building and not starting them very often during storage it what seems to weaken them the most.
I use the aggressive cut chains (instead of the low kickback type) on all of mine with a 16 inch bar and they get a workout as the lighter weight limb trimmers after the tree is down during firewood season. Some of mine have the spikes but really do not need such if the chain is sharp and aggressive cut type. I usually use the bigger heavier more powerful 20 inch up saws for felling and cutting up the trunk section of a larger tree.
Some of the HDC kits that are not Walbro are really iffy and not quite correct. Close but, but.
The $16 OEM WALBRO K10HDC kit is more reliable but also keep a heads up about the needle size. If you drop a new needle in and the metering lever Heigth changes is a heads up that something is amiss. Here is a Walbro.com service manual link to get Walbro IPLs for their carbhttps://www.walbro.com/service-manuals/s or if this link don't fly just search Walbro.com service manuals and then click on HDC. I think some EZ's used maybe a Walbro SDC and some older EZ's may have had a Tillotson carb
AND two type of the HDC a dependent and independent as explained at the Walbro site and in the link I provided about how to pressure test.
Also here is a link to some good info about how to pressure/vac test the HDC carbs.
Little bit more info here in this thread than on Leon's video site about them. You can also nose around on searches and find info about testing the carb's check valves which were not really intended to be a serviceable item.
https://houseofhomelite.proboards.com/thread/10216/homelite-procedure-carburetor-pressure-testing