I have one last question? You said you rebuilt the carb. How are the needle valves set? Are thet set per the manual? Now that the ACR is ruled out and with a new coil,points,condensor and wiring issues addressed I am struggling now. Did you make sure the old carb gasket was completely cleaned off the engine block surface and the mounting surface of the carb? BTDT For what they cost I would put on a new plug wire as well.:bigthink:

You are correct in suspecting the carb. it was my fault. I didn't really tight the bolts. So it wasn't seated well.

Now what we have is... a running tractor! it sounds good but there is a knocking type noise emanating possible from the engine. I looked around to see if anything was loose or not tighten down i didn't see anything. I made a video. not sure if the sound will be all that audible though. The noise is more prominent midway from low idle to high idle. Other then the knocking noise it seems to be running good. :Pray:

I'll post the video in a minute. it uploading...

Looks to be vibrating quite a bit. A few questions for you. All 4 motor mount bolts tight? Check your drive shaft to trans input for being loose? I'm assuming you took off hydro pump belt to isolate the noise? Did this just happen after you adjusted valves?

I don't think it sounds all that bad. Prolly the knocking noise is a wallowed out drive hub or the PTO clutch rattling a little. I guess I would try tweaking the main adjustment needle on top of the carb to smooth it out a little. Alvy I think the vibrating is him with the camera. Sometimes we all overlook the simple things.:beerchug:

yes you are are correct. I took it off for the purpose of illuminating it as a cause. The engine bolts are tight. the engine itself is secured to the frame. The Drive shaft to transmission does have a very slight looseness to it. the sound of the shaft being jiggled does kind of sound like the noise I hear while its running. But it's hard to say.

Another problem arose however. I came in for awhile and when I went back out the coil had boiled and the internal fluid/oil was bubbling out from the seems. So whats the story about that? I recall reading a thread some time ago, about someone having this issue. I think it was because they left the key on. Could that cause it? Because I do have to admit I did leave the key in the ignition and turned on. My 100 actually has a toggle switch and a starter button because I took the ignition key out. I guess I'm not used to taking the key out.

possible rattle
 

Coils go bad for no givin reason. Pretty sure the coil windings deteriate and short out. My old 125 smoked a coil couple years ago. Oil boiled out same as yours only I was mowing the yard. When you get another coil make sure it is equipped with an interal resistor.

I ll have to look it over more so tomorrow when I get a new coil. The clutch on the 100 rattles a lot so you could onto something there. The 125 has more compounds under the chassis then the 100 does. The 100 is really the only cub I have owned before this one. I really like cubs though. I wanted a hydrostatic transmission to mow with so I bought this one late last year. I haven't really had it running until this spring.

I haven't watched the video yet, but it is possible your knocking noise is your PTO, as a couple others have mentioned. they have anti-rattle springs that often fall out or are forgotten or eliminated by previous owners. testing this is super easy. with the engine off, engage your pto (lever forward) and grab the pto pulley and turn it back and forth. if it has some wiggle room, there's your knock! make sure you've got your key in your pocket so you dont accidentally leave it in the on position when you try this. Glad you brought your 125 back to life, they're one great little machine.:beerchug: