I want to thank everyone of you who responded to my original question about my TroyBilt engine replacement. I completed my exchange with the 6.5 HP Harbor Freight Greyhound version of a Honda clone.
I had to also replace the 4 engine mounting bolts with a 5/16 X 1 - 24 thread because the original Tecumseh had narrow threads. The 5/16 X 1 1/2 - 24 thread bolt for the end of the shaft that secures the drive pulley was also replaced because the original bolt has narrow threads.
If you are thinking about trying an engine replacement I may share some hints:
1. I removed the bolt to the rear of the drive pulleys and reversing disk. This gave me access to the inside of the pulley as it fits onto the engine drive shaft. I sprayed PB Blaster in the area and left it sit for 36 hours. It may have helped.
2. Slide the belts off the pulley and slide the dual pulley away from the frame. It will give better access to the 4 mounting bolts.
3. If you remove the bolts at 2, 5 and 7 o団lock positions (looking from the handlebar) you will be able to twist the old engine a bit to give better access for removing the final bolt located at the 11 o団lock position. If the belts are out of the way a ス socket on the end of a wobble extension will work. A ス ratchet type wrench may also be helpful.
4. When I began the reinstall I used my floor jack with a plywood platform to align the drive shaft through the frame so I could start the first engine mounting bolt (11 o団lock) first.
5. My original engine had 4 shim washers on the shaft to align the drive pulleys. I used 2 washers, a total of 1/8 on the new drive shaft to get the proper alignment with the drive pulleys on new engine. I haven稚 reconnected the throttle cable yet.
6. My best wishes to everyone else wanting to do their own exchange. If this information has been helpful to anyone else, I am rewarded. Others have helped me so much in the past. This forum has been extremely helpful to me. I check it often and try to assist other when possible.
I tried to share a photo of the drive pulleys pushed to the rear. You may also be able to see one of the holes where a bolt was already removed. Look closely at the photo of the socket and bolt. A small piece of paper towel was used to wedge the bolt tight so it didn稚 escape during the reinstall.