Small Engine Troubleshooting Problems? Ask a Mechanic Now.
If you can keep it running by being choked, there is something in carb jet. Even though it is a new carb, it can happen. Remove carb and blow compressed air into center jet (better to remove jet). run a small wire through the jet if you have one just to make sure all is clear. Let me know the outcome
Is it an actual Honda OEM carb or aftermarket? I have had these same issues with aftermarket carb even though new. I usually just end up having to replace the carb again. I can OPT OUT and let another expert try to help you with this issue
It could but rare. Its rare that you have to adjust Honda valves on these engines. Have to be careful not to get too tight, or you will ruin the engine.
Intake should be 0.006
Exhaust should be 0.008
you can +/- 0.001 on either side if needed .
I normally stay -0.001 on each side to be safe.
How r the Governor spring(s).
those are great motors. before I done small engines, I layed block/brick and has 2 mixers . one with a 5hp Honda and the other an 8hp. never a running issue. very dependable engine.
I would check the valves then and see what they are set at.
How were the valves? It sounds like you have done everything I would have done also. Let me know how the valves are. I will keep searching for possible issues