TO-30 carburetor and governor adjustment

I have checked and cleaned all filters, including the "secret" filter and the one above the sediment bowl and also removed and cleaned the screen from inside the tank above the bowl assembly. The fuel runs steady to the carb, and also steady from the drain at the bottom of the float bowl.

I suspect that possibly the governor needs to be adjusted, because when I press against the governor with the throttle wide open, I get the RPMs that I used to get (until this season).

Now for my question: First, the carb on the tractor is a Marvel Schebler TSX 33, probably replaced some time before I got the tractor. Will this carb work correctly for the tractor, and does anyone know how to properly adjust it? Using info I found here on the board, the Main jet and air/idle jet adjustments don't work. The tractor will only run smooth if the Main jet is about 3/4 turn open. The air/idle screw doesn't seem to make any difference no matter where I set it.

Second, if I attempt to adjust the governor (per instructions supplied by John-UK, Thanks John!) will the different carb have any effect on the governor adjustment?

Sorry for the long post. Any help is appreciated.

Tom

Jerry/MT- You were right on the money. I had a "fat, bluish spark", but the plugs were covered with thick, black soot. I have replaced them for now, and will be looking for the right carburetor to relace the TSX 33. Also, as you suspected,the timing was way off, but now is set correctly. Since the tractor seemed to start and run smooth, I didn't even think to check the plugs or timing.

John- I followed the procedure that you supplied to me to re-set the governor, and now can get top speed out of the engine. The procedure sheet is well-done and pretty easy to follow.

Thanks again to both of you. I hope some day that I can contribute back even a fraction of the knowlege that you guys bring to this board.

Tom

The correct carburetor for the TO-30 is the M-S TSX 458 or the Carter 997S(rarely used but designed for the -30). I'm not sure what the TSX 33 was used on but I suspect the Ford N series.
It may have an oversized main jet or a smaller venturi, (or both) in it to cause the problem you are seeing with the mixture. My guess is that the carb wants to run overly rich because of the aforementioned jet/venturi configuration hence you don't get any effect from the idle air screw. Check you plugs for carbon fouling(dry sooty deposits)and that will confirm an overly rich situation.
If that is the case, you need to get the right carb configuration or you'll always have this problem. I think that if you can find a TSX 458 or the venturi from the same, putting in a kit with the right jet may solve the mixture problems.
You say it "it doesn't seem to run as fast as it used to...". Did you measure the rpms at a fixed throttle position before and recently to come to that conclusion? That could indicate a governor problem. You said the fuel flow is steady from the bottomm of the carb when you checked it. Steady is good but it should really gush out of the bottom drain like a cow peein' on a flat rock. Does it do that? If it doesn't, your fuel delivery is restricted somewhere. Make sure the fuel cap vent is open and not restricted. Check the fuel line for kinks make sure that carb float is not hung up, or that there isn't a lot of crud in the carb fuel bowl that's holding the float partially closed.
My advice to you would be to:

1) check the ignition system,
2) re-check the fuel delivery system unless the fuel really gushes out of the carb fuel bowl drain, and,
3) if all the above check out fine begin to suspect a problem with your carb.
As far as the throttle-speed relationship, that could be a problem with the governor.