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Honda HRX 217- model # HRX217K5HYAA- Honda engine model# GJAAA- 3423191
Issue- when engine warms up it surges.
What i have done so far-
Cleaned carb in ultra sonic cleaner 3 different times including pilot jet- main jet- and nozzle.
Put all new gaskets ( yes and in order) , filter housing and isolater block. Only original part is the carb.
1st time I started it up it ran great. Noticed a little leak around the carb bowl- so I pulled it back apart and fixed the bowl gasket. Put everything back on engine. Every start since then engine runs great for about 30 seconds until it warms up and starts surging.
I've pulled this thing apart probably 10 times with the same results and can not figure out whats wrong. I can spray brake cleaner around the isolater block on the engine side and it will smooth out some. Thats why I put a new block and another set if new gaskets on. No difference.
When I first got this unit the filter housing was broke and the bolts seemed to be about out of threads, so I tapped some different bolts in and everything seems to tighten up just fine.

Any help would be appreciated!!!

does it smooth out still when you spray brake cleaner with the the new gaskets and isolater?

It does somewhat. Now I'm wondering if the thermawax is not opening the choke. Will put it all back together in a bit and check.

usually surging is it's running lean, a choke makes it richer. but it may be the problem. easy to find out.

It sounds like it's still a carb problem. I have taken the cap limiter off and taken the idle adjustment screw out and cleaned that good with carb cleaner. Follow the path ways with carb cleaner and fine wire like out of a wire brush or bread wire tie and compressed air. If you decide to remove the cap on the idle screw take a soldering iron and heat the cap up and it should pull straight off. Count the turns when removing the idle screw so you can install it back to the same settings. Sometimes the path ways in carbs are so small that ultrasound doesn't always get them clean and manually checking is the only way. Hope this helps.

Providing you don't have an air leak, don't overlook the valves. If your valves are not opening as designed due to excessive valve lash, your engine will also run lean. Heat the parameter of the valve cover (I remove the fan cover and air filter box so I don't melt them) and you should be able to peel it off and reuse it. Intake: 0.006" (0.15mm) Exhaust: 0.008" (0.20mm).
I'd be willing to bet that since you have cleaned the carburetor so many times with no change, the valve lash is were your problem lies.

Thanks for the replies- figured out the idle jet just needed to be drilled out a little and now it purrs like a kitten. Thank you