Small Engines (Lawn Mowers, etc.): runs only on choke, diaphragm type, riding lawn mower


Question
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Followup To
Question -
Have an eight-year-old Cub Cadet 2165 riding lawn mower.  Have used it once this year for two hours, ran fine.  The second time used, it ran for one hour, then began faltering.  Would run only with the choke pulled out, and even then, would not build up the horsepower.  Would stall when choke was pushed back in. Tried replacing the fuel filter, no improvement.  Took off the Mikuni something-or-other (diaphragm-type carb? - I'm not sure), took it apart, sprayed carb cleaner, re-assembled - no improvement.  Can you help?
Answer -
 Hello Dennis:

 Could I have the Engine Make, Model and Size please? It Sounds like the Carb, but Depending on the Engine Model and Make and Size I hate to safe thats it.

 Respectfully

 John


It's a Vanguard V-Twin 16 hp.  

Answer
 Hello Dennis:

 Thanks. That helps.  Ok. If you are 100% Sure the Carb was Cleaned Good. Then you Need to do a Compression Check. The Valves May Need Reseating. If it were Me; Id Look at the Carb Again. Blow all the Ports and Passages out with High Pressure Air and Replace Old Parts With New Ones from a Kit. Hope this Helps.

 Good Luck

 Respectfully

 John