1957 D14 - Carburetor Question

[Bergmann]

Hi All,
I recently bought a carburetor rebuild kit for my 1957 D14. It's the Marvel Schebler TSX280? carburetor. The rebuild went well and after I reset the timing and did a tuneup (plugs, plug wires, coil, cap, rotor, etc.) the tractor fired right up. I'm finding that I need to open the choke 100% to start the tractor and once started, I back the choke switch to about 60%. I can't pull the choke lever back to 0%, or the tractor dies. I can't leave the choke lever at 100% while running, or it runs too rich and starts to die. I'm new to carburetor rebuilds. Recently, the tractor sounds a little rough (barky) while running and I find myself regularly tinkering with the choke position. I followed the carburetor rebuild kit guidance by backing both needles out 1 turn. I've tried adjusting both needs a little bit while running, but haven't noticed much of a difference at idle or when the tractor is running. Any advice on getting the tractor to run smoother or whether I should make adjustments to the choke/carb are appreciated. Thanks!

 

[Jim.ME]

Marvel Schebler TSX 670 was the D14 carb. I don't know the differences between the 670 and the 280 you have. Standard Motor Products shows the same basic kit for both, however the venturi or jetting maybe different. I have owned and worked on several D14s, and they all had the TSX 670.

A bit of digging on another carb parts/rebuilder's website says the: float, base gasket, venturi, nozzle, economy jet, power jet, and throttle shaft are different in the 280 compared to the 670. I can't guarantee the accuracy of that info, but it wouldn't be surprising if it is correct. External looks doesn't always tell the story.

You can likely get it to run ok, performance and fuel economy will be unknowns, but it may take a bit more tweaking. 1 turn on the jets is just a starting point. Try turning the main jet needle 2 turns out and about 1-1/2 on the idle mixture jet, then try adjusting from there.

 

[Bergmann]

(quoted from post at 10:38:03 02/08/22)
Marvel Schebler TSX 670 was the D14 carb. I don't know the differences between the 670 and the 280 you have. Standard Motor Products shows the same basic kit for both, however the venturi or jetting maybe different. I have owned and worked on several D14s, and they all had the TSX 670.

A bit of digging on another carb parts/rebuilder's website says the: float, base gasket, venturi, nozzle, economy jet, power jet, and throttle shaft are different in the 280 compared to the 670. I can't guarantee the accuracy of that info, but it wouldn't be surprising if it is correct. External looks doesn't always tell the story.

You can likely get it to run ok, performance and fuel economy will be unknowns, but it may take a bit more tweaking. 1 turn on the jets is just a starting point. Try turning the main jet needle 2 turns out and about 1-1/2 on the idle mixture jet, then try adjusting from there.

Jim,
Thanks for the reply. I'll give that a try. My D14 is serial # 5223. The carb looks original, but I don't know for sure, as I bought it from a seller on Craigslist who knew very little about it's history. I should have noted that when I took the carburetor apart (originally), it was in a non-running state. I could get the tractor to fire on starting fluid when timed, but it wouldn't stay running. When I took the carburetor apart I quickly realized the carburetor was missing the venturi. I researched venturis online and found that they come in both plastic and metal. (Aluminum? not sure) I ordered the metal $30+ venturi and it appeared to be a match and fit well. I did confirm the float was 1/4" away from the plane of the carb face, and the float looked to be in good condition.

 

[Jim.ME]

I don't find a serial number break in the parts books for a carb number change. TSX 701 and TSX 670 were the early ones and TSX 815 was the service carb used when a carb replacement was needed. My 1957 D14 has the 670, as did the two 1958s. So, I very much doubt your 280 is the original carb. Externally many of these carbs look the same, and will bolt up, however the internals are the difference.

As I posted before it appears the jets used were different and it may be profile, not just how it fits, on the venturi. They were pot metal, not plastic back then.

When you went through the carb did you use something like torch tip cleaners to probe every jet and passage? Then blow out the passages with carb cleaner followed by compressed air. If it is clean and the passages are all open, you may get it to run reasonably well by working on the adjustments as I said before.

 

[Bergmann]

Hi Jim,
That's very interesting, thanks again. I soaked the carb in carb cleaner and blew it out with compressed air. I also used a flywheel to clean the surfaces I was able to reach. I'm not familiar with torch tip cleaners... I will need to look into that. It did look quite clean by the time I was finished. (See images)

[/img:8f7e0a2c64]

 

[Jim.ME]

(quoted from post at 15:07:43 02/08/22)
Hi Jim,
That's very interesting, thanks again. I soaked the carb in carb cleaner and blew it out with compressed air. I also used a flywheel to clean the surfaces I was able to reach. I'm not familiar with torch tip cleaners... I will need to look into that. It did look quite clean by the time I was finished. (See images)

[/img:b60d8c7eff]

Tip cleaners are a series of small wires used to clean the holes in torch tips. Use them to probe all the small holes bored in the carb body sections to dislodge dirt or rust that may be stuck in the passage. when running the tips through brass jets get as close to size as you can but don't oversize the jet hole. Make sure all the holes are open in the sides of the brass nozzle tube as well. Most places that sell welding supplies will have them.

 

[Nordic]

I fully agree with Jim about the setting of the screws. Be sure to run the engine at full throttle when you adjust the big screw. Turn it in each direction 'til the RPM drop, this way you will find the sweet spot close to the more generous setting. I will share what happened with one Allis my Dad bought. It acted exactly like you described yours, physically the carb looked like it should (MS carb) but it turned out to have come from an application with smaller cubic inch. Once we discovered this we installed an original size carb and it ran perfectly.

 

[stevieb49829]

Also, check for a vacuum leak at the intake manifold flange. Warped carb top, pitted manifold, etc could be letting a lot of air in. But, I think you have a plugged passage in the carb, like Jim is saying.

 

[Dick L]

I have read and reread your post and I may not understand your terminology. Does it only start with zero choke or with full choke.

When starting a tractor on a rebuild I do the one to one and a half turns out on both. After starting the tractor I set the idle and the
stop screw on the back to get the idle speed I want. When it is set I leave it alone until I rebuild again. I the porn the throttle wide
open. adjust the engine speed to its fastest RPM and then turn it back in until I notice a slight reduction in the RPM's. I am then done.
That will be the best unless you put it on a dyno where you can check HP.

If it was barking before the rebuild and needed choke adjusting other than having it open it suggests you have fuel restriction. That can
be anywhere from the gas tank to the power jet which with this carburetor fairly visible looking into it where the needle seats when
closed.
I would remove the plug in the bottom of the carburetor and see what kind of flow you have after the bowl is empty.

From there it would be checking the condition of the engine vacuum. A quick check is the palm of your hand over the carburetor with the
engine running to see how it pulls on your hand. Years ago I posted pictures of a manifold I sectioned to show where I found a hole
between the intake and exhaust. Valves have to be bad enough that your power is way down to cause you to have a carburetor act that way. A
bad gasket can alway give you fits. My guess is it would be unlikely to change just rebuilding the carburetor.

 

[Dick L]

I didn't porn the throttle wide open. (I then place the throttle wide open,) ^D