MdStamen And I dis-agree. Yes 4 cycle engines may have problems when they are ran in some positions too long. But they can be repaired easily. Unless the engine is locked up.
Then you haven't seen the damage I have seen on the newer ones. Once they start blowing oil through the PVC vent it is all she wrote; unless, you like short blocking for free or nearly free labor. There is a a lot of work disassembling and reassembly just to get one working again. A half day at least when you know what your doing.I don't even brother any more if when I drop the air cleaner and it is full of oil. These engines were never locked up but still never would run; unless, short blocked.
Or try replacing a timing belt on half shaft design for you must disassemble the crankshaft by pressing it apart. Some newer designs are using gear driven system but once one of the arms that drives the push rods breaks, again it is a short block time.
Once the rings and cylinder are damage there is no rebuild parts except for a short block.
I just got done sending a half a pickup truck load to the recycler.
Now repairing a carburetor is child's play and when it is a Walbro or Zama cube or rotary using OEM parts which I can get less than the Stens kits. Even some of the Ruixing carbs are repairable if you know which Zama gaskets and diaphragms will work as many of the Ruixings are Zama clones. BTW the Walbro W tool will not work on all the the Walbro cubes and rotary carbs. The WTE is good example of this where the tool is off by .039"
For buying complete carbs be extra carefully getting them off Ebay as some are rejects that some just on unsuspecting buyers. Even new replacement Ruixing carbs may need to be rework just to get the engine to work correctly. I know of at least two Ryobi blowers here that I had to modify the choke vane just to get them to stop flooding at start-up.