Check ball should be included in a new rebuild kit. Might even be an extra part or two depending on the model.
You'll want to pull all old check ball or other parts anyway for proper cleaning; whether that's with a magnet or simply turning the bowl upside down it should still happen. Recommend a good, clean, flat workspace with a clean shop rag to catch anything/everything for the latter, mainly for inspection and comparison purposes. And if you've never been through this particular model before, also recommend a good perusal of the exploded view diagram before doing anything else. (Also usually included with the rebuild kit, if a manual is unavailable.)
Be careful during reassembly:
- Not all check ball or other part measurements are the same. Pay attention to sizes and placement when replacing old parts with new. If diameters are obviously different in the reassembly instructions, use a micrometer even if they look the "same" to be sure all is getting to the right place. This can make huge differences in performance, and incorrect placement could even keep the carb from operating altogether.
- Do replace all parts available from the rebuilt kit, even if they don't "look" like they need replacement. I can't stress this enough. I think everyone's done it. You're tempted to "save parts" or "be conservative" in this area. (At least I have been.) "I'll use that new needle later, mine's fine." "These old check ball and rod parts look fine. I might as well save the new ones for when I really need them." ....Don't. ...Don't fall in to this time-trap. Trust me, you'll get the whole thing back together, and something won't be right or it won't flow at all or it flows too much and no adjustment solves the issue. And you're sitting there thinking, "dammit, I had the chance to replace that [part], and I didn't do it. Back to the workbench." A rebuilt kit is, what, fifteen, twenty bucks at the most? (Yeah, I know you racing guys pay lots more.) What's your time worth having to rebuild carbs over and over? The point: cheap insurance. Also, those new parts you're "saving" in the kit - when exactly are you going to use those again? ...That's right, probably never. Do yourself a favor and use them now. Look at it this way, you could be preventing the next component failure without even knowing it.
