Started the 123 rebuild tonight!

[pulse301]

Now that I'm back from my business trip I was able to start the rebuild of the 123. I know of 3 things that I had to do to start with. First, the fuel shut off was leaking if it wasn't completely open or completely closed. I removed the tank, took of the shut off and took it apart. I noticed that the little gasket, or o-ring, or whatever is in the little nut was cracked, the obvious reason why it is leaking. I found a new one on ebay for just $10 including shipping, so I'm going to replace the whole thing, since I'll get a new screen and all.

Next, the plug wire boot was ripped. I guess that isn't really major, but the plug wire is probably 40 years old, so I might as well find a replacement for it.

Finally, the muffler has a hole in it. This is where I need a lot of help. I removed the muffler fairly easily. After taking it off I immediately noticed stuff rattling around in it. I have pictures of the stuff that fell out, that I'll post, and a picture of the hole. So I have 2 parts to the question. Do you think the combination of the whole and the broken metal inside the muffler could have caused this knocking sound:

My YouTube video at 1m 16 seconds where you can really hear knock

And secondly, what should I replace the muffler with? Should I go with a used one/new one just like the old one? Or is there something quieter out there that would fit just as well, maybe even better. I'd like to have something smaller and quieter that dumps out on the left side of the tractor instead of going all the way across the engine. Or is there a specific design reason for the stock muffler? Please keep in mind that my goal is to improve this tractor, not restore for showing.

Here is the picture of the hole:

Hole_in_Muffler.jpg

Here is a picture of the metal covered in carbon that fell out of the muffler:

Junk_In_Muffler.jpg

Thanks for the help!