"This morning it was loose again and I ran it without the plug"

?? Good trick, shouldn't use much gas that way.

Sounds like it is tear down time.

Walt Conner

O.K. where do I start and what should I look for? Any idea what may be wrong?

Charles

based on what very little you told us, prolly time to take mower or engine to a qualified shop - or replace the machine.
If you ran that engine for any significant period of time under load while it's crankcase oil was contaminated with raw fuel, serious engine damage could have happened - as the contaminated oil would have lost it's ability to lubricate...

Well, you had best take RCBE's advice, and trash that engine, or at least, seek professional help, to find out if it is rebuildable! Which i sincerely doubt! It will probably be cheaper to buy a new engine, read the instructions fully, and install it in your machine.
BUT!!
Depending on the age of your machine--it might be better to just buy a new machine, and get a fresh start. And--definitely read the book that comes with it, and follow the rules contained therewith!
What caused the problem with the old engine, happens to a machine when proper care and feeding of the engine isn't followed. Also allowing it to set around for a long time, causes it, too. Plus if you didn't religeously check the oil, and change it every spring or fall, could have caused the problem.
When the engine is not used for a while, things happen--the oil leaks out, or gets contaminated by water, or gasoline, the carb gets gummy inside, the float sticks open and floods the engine block with gasoline, and ya try to start, if it only runs a little bit--it will probably up-chuck its guts---and there ya will be! Right where ya are now!

Thanks for your input. I had more or less figured out I need to get a new machine. However, since I have the time, I plan to tear this one down and see where the problem is. At the least I will get familiar with the engine. So, next week I'll take the carb out and clean it out.

Well that isn't going to hurt anything but sure isn't going to help your problem.

I can send you a PDF copy of the Service Manual for that engine IF you like. Address below, put in proper format and remind me, model number, etc.

Walt Conner

I see the main probleem with powered lawn equipment as this:
Kids would hide car books in their math or english books.
Kids would spend more time looking out the windows.
Kids always thought they could learn lots of things out by the lake, sleeping under a tree, instead of paying attention at school! (I had one of those!)
Adults who never read the book that comes with the machine!
Adults who never take advice!
And, folks who ---well---never mind!

And folks that browbeat every new poster, but offer little to NO actual help.
Ever wonder why so many posters never respond again after Rusty "helps"!

Gee, thanks Bill for the vote of confidence! Really made my day! Rusty