Small Engines (Lawn Mowers, etc.): running and idleing, carburator, gas tank

Question
i have a early 90's model murray classic 3.5horse power oush mower throttle free design.I have recently had to replace the piston and rod assymbly set the timing back on the cam and crank. My question is since i put it back together it idles just fine setting still but when u start putting it through the grass to cut the engine bogs way down and about cuts off but u can move it back and it takes minute but it will idle back up if it shuts down its hard to start back unless u let it set a few minutes if u have any ideas on this please let me know thank you.

Answer
 Hello Bruce:

 From your Description I suggest you; 1- Check the Gas Tank Cap and Ensure it is Venting the Tank Properly. 2- Clean and Rebuild the Carburator. It Sounds like the Gas is Being Restricted to the Bowl or the Caburator Jet. The Restriction to the Main Jet will Cause the Problem you Described. The Jet is Open enough for the Engine to Idle, but when a Load(Grass hitting the blade) is Applied it Cant get the Required Gas to Run. Gas Forms a Varnish and Over Time this Varnish Builds up and Restricts the Gas Flow to the Carburator Jet. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. I enjoy knowing the Outcome. Thanks.

 Good Luck

 Respectfully

 John