Marvel Schebler TSX tractor carb rebuild

[Steve]

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.

I'd like to get one of those kits for my VAC. Just no issue with the points so why spend the money? Wait till it craps out!

 

[FergusonTO35]

I installed mine when it was time to change the points and glad I did. Starts easier and plugs stay much cleaner. Another reason I think my troubles are fuel related: I don't observe much fuel flow through the inline filter, even with the shutoff opened all the way. Just a little trickle, and not much fuel accumulates in the filter.

 

[Steve]

I installed mine when it was time to change the points and glad I did. Starts easier and plugs stay much cleaner. Another reason I think my troubles are fuel related: I don't observe much fuel flow through the inline filter, even with the shutoff opened all the way. Just a little trickle, and not much fuel accumulates in the filter.

You still 6v?

The biggest inprovement for my VAC was 12v conversion. It will fire right up cold with no choke down to about freezing. It will even start with the hand crank super easy. Usually one crank hot, two cranks cold!

I have found that the paper fuel filters never really fill completely in a gravity system. Your sediment bowl head may be corroded and restricted. Or just filled with crap on the inlet from the tank.

 

[Larry B]

I put a pertronics kit on my IH 184 years ago. Money well spent. I also changed it to a "cold start" ignition. I replaced the 3 ohm coil with a 1.5 ohm coil with 1.5 ohm ballast resistor. When i engage the starter it bypasses the ballast resistor to get better spark energy while cranking.

 

[FergusonTO35]

Tractor is 12 volt, using a Delco one wire alternator.

I put a pertronics kit on my IH 184 years ago.

IH was building tractors in 1837?

 

[Larry B]

Tractor is 12 volt, using a Delco one wire alternator.



IH was building tractors in 1837?

It is a 1975 184 LoBoy. It has a C60 engine that goes back the the original Cubs. I guess that does read a little funny.

 

[FergusonTO35]

Oh I know, just couldn't resist. Here's a new wrinkle. Looked at the tractor again this morning and now the inline filter is 100% filled with fuel. Maybe it had an airlock that was blocking the fuel. I shined a light down in the tank and was shocked at how clean and shiny it is. Other than some floating bits of junk it was really clean. I 'spose I'll hook up the finish mower and try it out before I do anything else.

 

[FergusonTO35]

Ok guys, looks like the carb is indeed the culprit here. Gotta sump full of gas!



Went ahead and ordered a Sparex carb to use while this gets sorted out.

 

[Steve]

Ok guys, looks like the carb is indeed the culprit here. Gotta sump full of gas!

View attachment 287331

Went ahead and ordered a Sparex carb to use while this gets sorted out.

You needed a good engine flush anyway!

 

[FergusonTO35]

Yeah, after 67 years she is due for one!

 

[Larry B]

With gravity fed tractors and mowers it is not "if" but "when" the needle doesn't seat and you either get a sump full of gas or a floor full. Old tractors had a fuel shut off for a reason. You never parked the tractor overnight with the gas on. Sooner or later it will get you.

 

[Steve]

Ok guys, looks like the carb is indeed the culprit here. Gotta sump full of gas!

View attachment 287331

Went ahead and ordered a Sparex carb to use while this gets sorted out.

Wait a minute, how did you get a crankcase full of fuel with an updraft carb?

 

[FergusonTO35]

The fuel tank sits above the engine. I imagine that there was enough fuel in the tank to push its way up the manifold and into the engine. Lesson learned!

 

[Al Smith]

I've cussed these things for at last 45 years . On my TO-20 I just have a ball valve fuel shut off and should put an inline filter on it .It doesn't take much dirt in the tank to cause them to flood which is just a carb clean .
I completely rebuilt the Marvell -S on my OC-6 Oliver crawler a few years ago with a kit that had all the parts including the main jet .That main jet BTW takes a 1/4"- 40 tap to clean up the hole .The crawler does have a sediment bowl .
Saying all that it looks like I'm going to need to give a little attention to the Fergy .I noticed the other day at idle it was running lean and needed a partial choke to smooth out .It's probably a twice three times a year thing I do on that old tractor . That old duffer has been around the horn, has slugged main bearings, shim stock under the inserts .To repair it right would take grinding the crankshaft mains about 20 thou under and replace the mains .Weather that ever happens remains to be seen .

 

[Al Smith]

Those little pups are built tough, you'd have to work at it to kill one .You'd about need to run it out of oil to do the job .Even then if you have a block the whole thing could be rebuilt .Heaven only knows how many after market concerns make replacement parts .

 

[FergusonTO35]

Agree totally. This has been a great tractor and I don't mind putting up with some aggravation. Not many things can give faithful service for 60+ years while asking for very little in return.

 

[Al Smith]

I got to thinking about this .Usually with a stuck needle float valve it just dribbles out the choke side .However if you had the hose connected to the breather it could raise high enough to get into the manifold and flood the crankcase .I should but I don't have the hose connected .Fact I have no idea where it's at .

 

[FergusonTO35]

The hoses were connected, I guess that means they are sealing good. The Sparex carb came today, it looks respectable. Even has a model number tag like the original.

 

[Al Smith]

Looks like a stainless steel main jet .Looks like costly also .

 

[FergusonTO35]

It was only $70.00 on Amazon. I sent the original to Larry B for rebuild.