Super MD TA Carb

[bvaughn85]

Hi everyone.

Been working on a MDTA and recently rebuilt the carb. Tractor would run on gas side before rebuild but had to be on full choke. After rebuild, tractor will not idle up and is smoking black pretty heavily. Runs at a very low rpm. Took carb back off to check mixing valve and it is set at 4/32 or just a little shy. What did I miss. Any help would be appreciated. Not much literature floating around on these carbs.

Thanks

 

[Janicholson]

Float level too high, or choke not adjusting. Air cleaner or hose issues are also possible. They do need to be rich to run, but not to excess. Jim

 

[redforlife]

Something was likely plugged up before rebuild. So, that problem likely is no longer an issue.
Are there adjustments that can be made while carb is on tractor. If so, did you try adjusting while carb was on tractor with engine running? Sounds like it's to rich, and something needs to be adjusted leaner.
By the book adjustments, are often just a pre set starting point for bench assembly.

 

[bvaughn85]

There is no adjusting needles on these f8 carbs. Everything is fixed. Just mainly trying to figure out why it wont idle up. From what Im gathering. These carbs tend to run a little rich right out of the gate. Choke and air breather are all opened up. If we pull choke it will pretty much die instantly.

 

[redforlife]

I don't think your problem is (not enough) gas. Or choking wouldn't kill it out. I think your problem is, it's way to rich and choking itself out without even using the choke. These might naturally run rich when set right, but sounds like yours is borderline set to rich to even run. I'd lean it up just a tad. Just enough to see if there is a difference. If so, you can adjust further for your liking. Or if not, you can adjust back to where you started, and you haven't lost anything except your time to find out.
It just sounds like it's to rich, where it currently set. If not, the choke should of helped it, and not killed it out.

 

[bvaughn85]

I would agree with you. Our big question is how is that done. There are no adjusting needles or anything on this carb.

 

[caterpillar guy]

My vote is the float is to high or restricted air flow in change over butterfly i manifold.

 

[Millwright]

Check to see if the diesel throttle is shutting off properly, it is possible to have injection on the gas side.