My zero turn RZ4623 will start & run fine in idle, but with blades engaged it only runs about 20 to 30 minutes, and quits.

SOURCE: craftsman zero turn model# 107.27774

If you are jumping the solenoid and it cranks but wont start leave the key in the on position and give it a try. Try replacing the solenoid and the wires conecting it to the battery.

SOURCE: Stalls when engage blades in forward, but cuts fine in reverse

Did you try to disengage the safety feature that should shut the tractor off when the blades are engaged and the tractor is placed in reverse? I believe that it is located under the shift leaver

SOURCE: once engaged and start mowing, you can mow for

I have the same problem with mine and its not the air filter. I have a new filter and cleaned it and still does it. I even took the air filter off and it still does it.

SOURCE: Poulan Pro riding mower jerks in forward and the blades engaged

This is a lawn mower catagorized as a chainsaw. We don't answer lawn mower questions ands you don't cut down trees.

SOURCE: tractor starts, stalls when blade is engaged, or brake released

you have a safety switch malfunctioning or a transistorized relay not working properly. Go to www.partsdirect.com, this is sears website. It should be able to find and illustrated parts list for your mower.