Marvel Schebler TSX tractor carb rebuild

[FergusonTO35]

Most 1940's-50's Ford and Ferguson tractors are equipped with Marvel Schebler TSX series carbs, as is my 1955 Fergie TO-35. She is long overdue for a cleaning and rebuild, I'm also going to install an inline filter in the line. Anybody have experience with these carbs? They look pretty easy, but I also don't have much experience working on carbs. I believe mine is a model TSX-605, MF part number 181532M91.

 

[Larry B]

If it is a gravity feed system sometimes you can get away with an inline filter made for riding mowers. Automotive type filters are designed for systems using fuel pumps. Depending on the micron size of the filter the surface tension of the fuel may stop or restrict the flow of fuel and be dependant on the level of fuel in the tank. There is a reason the old gravity feed tractors use sediment bowls. You can use an inline filter without issue if you also install a small electric fuel pump.

 

[FergusonTO35]

Thanks bro. Went to Napa today and got new metal and rubber lines, also a #3001 filter which I have used before on other gravity feed systems just fine.

 

[Steve]

If you can rebuild a chain saw carb then this will be cake! Make sure you remove the high speed needle before you split the carb. It goes all the way down to the bottom to the main jet and you can break or damage it. Most all the tsx carbs I have been in the throttle body has a warp to it and the throttle shaft bushings are worn. If you can find a decent priced replacement carb I would go that route. Unless you are after the original vibe, then by all means, give the carb rebuild a try!

I don't use a pleated filter in line with gravity systems. The sediment bowls with screen have never let me down. Don't bother rebuilding the sediment bowl. Just replace it. Most of them have been overtightened throughout the years and the base gets warped and you will never get a leak proof seal. When the time comes to clean your new sediment bowl use a new rubber gasket and tighten it just enough to make a good seal.

 

[FergusonTO35]

Thanks. I did go ahead and install the inline filter today. Took it for a test drive and noticed a big improvement. The sputtering was dramatically diminished, I may be able to iron out the rest of it adjusting the timing and fuel mixture. Still planning to rebuild the carb at some point though.

 

[FergusonTO35]

If it is a gravity feed system sometimes you can get away with an inline filter made for riding mowers. Automotive type filters are designed for systems using fuel pumps. Depending on the micron size of the filter the surface tension of the fuel may stop or restrict the flow of fuel and be dependant on the level of fuel in the tank. There is a reason the old gravity feed tractors use sediment bowls. You can use an inline filter without issue if you also install a small electric fuel pump.

I did notice that the paper element filter does not fill up very much in operation, probably due to the less porous element. I found the Wix 33971 has a nylon mesh and people report that it works well with gravity feed systems, so I went ahead and ordered one.

 

[Larry B]

I see it a couple times a year in my shop where people replace the little red screen filter on their mower with gravity feed with a paper element filter and complain of surging and poor running. Some filters will work, some don't at all and the best one is the one that works with a full tank and not with half tank or less.
Some old tractors have some rust in the gas tank that tends to clog jets in the carb. One fix is to use a fine paper element filter with an electric fuel pump made for riding mowers.

 

[FergusonTO35]

I have used paper element filters on riding mowers with good success, however I ended up going back to the screen style. I have been using the white B&S filters which are supposed to be a more fine mesh. May try the riding mower fuel pump idea, thanks for the tip. I'm sure my fuel tank has lots of crud in it, one more thing for the list!

 

[Steve]

I have used paper element filters on riding mowers with good success, however I ended up going back to the screen style. I have been using the white B&S filters which are supposed to be a more fine mesh. May try the riding mower fuel pump idea, thanks for the tip. I'm sure my fuel tank has lots of crud in it, one more thing for the list!

Rusty tank or just dirty?

How close is the TO to the Fords? Just by a new tank and be done? I know there is a lot of aftermarket support for Fords...

 

[Larry B]

I have used paper element filters on riding mowers with good success, however I ended up going back to the screen style. I have been using the white B&S filters which are supposed to be a more fine mesh. May try the riding mower fuel pump idea, thanks for the tip. I'm sure my fuel tank has lots of crud in it, one more thing for the list!

The red filter is 150 microns and designed for gravity systems. The white is 75 microns and designed for fuel pump systems. In practice i have not seen much difference and the white works on gravity systems. Some folks would be suprised how much dirt comes out of gas pumps. Especially when stations bypass the filters to save money because they are expensive.

 

[FergusonTO35]

Rusty tank or just dirty?

How close is the TO to the Fords? Just by a new tank and be done? I know there is a lot of aftermarket support for Fords...

The TO series are the direct descendant of the Ford N series and many parts are the same. New fuel tanks are available for around $260.00. The dirt that I have gotten out looks like dissolved gunk that accumulates on the bottom of tank. I probably should take it off and clean it really good sometime. I have a filter funnel that I use when filling it up nowadays.

 

[timg]

Just some more info on the sediment bowls used. Some have a fine mesh circular screen in the head of the bowl that it seats against. Others use a screened inlet in the pipe fitting screwed into the tank for the bowl. Just in case you are still having issues of fuel starvation. Of course that may be easier to see now with the clear inline filter you installed. Thought this may also help ya out.

 

[FergusonTO35]

Thanks. Mine uses the flat screen sandwiched between the bowl gasket and bottom of the valve. It also has a screen on the inlet elbow of the carb, which I cleaned out.

 

[FergusonTO35]

Well fudge, too good to be true. Took the tractor for another spin and we are back to spitting and sputtering. I am pretty certain this is fuel related though, its really predictable. The tractor runs perfectly for about 10 minutes, then the spitting and sputtering starts. Its not a total miss like an ignition problem, more like some of the power strokes have a little lean detonation. Idles smoothly all day long.

So, I am going to take off the inline filter for now and drain the gas tank. Going to observe how much crud comes out and if the flow starts and stops. Then off comes the tank for a good scrubbing. I think I'll replace the entire fuel shut off valve and bowl assembly for good measure also.

 

[Dustin4185]

Those carbs are easy to rebuild but can be tricky. I would at least drain, clean, and line the tank.

 

[FergusonTO35]

Yep, thats the plan.

 

[angelo c]

Sorry for the dumb question but is it a magneto or a distributor/coil set up. Marvel shebler carbs came on many small aircraft engines . The mags were rebuilt many times before the carbs...but avgas is different then crap mogas

 

[Steve]

Yes, weak spark can give you the same results of a lean condition. You could have a bad coil or primary side of the ignition problem.

Keep on with the fuel system refresh though. It sounds like it needs to be done either way.

 

[FergusonTO35]

Sorry for the dumb question but is it a magneto or a distributor/coil set up. Marvel shebler carbs came on many small aircraft engines . The mags were rebuilt many times before the carbs...but avgas is different then crap mogas

Its a distributor setup, I converted it to electronic with a Pertronix kit.

 

[FergusonTO35]

Yes, weak spark can give you the same results of a lean condition. You could have a bad coil or primary side of the ignition problem.

Keep on with the fuel system refresh though. It sounds like it needs to be done either way.

Never say never, but I've never done anything to the fuel system other than replace the bowl screen so that is where I am going focus right now. The ignition on the other hand has been gone through. I've added a Pertronix module and coil and changed the plugs/wires/cap/rotor within the last few years. The original distributor is getting a little shaky on timing but nothing major.