WTB allis b carb

Hey everybody,

Since I brought my first antique tractor (1939 Allis B) home I have had quite the roller coaster.

Everything has started to fail little by little and I am almost at my wits end.  Tractor was completely restored about 7 or 8 years ago and I picked it up with the snowplow fitted for it to take care of my driveway.

Starter needed a rebuild right away, no big deal, did it on my tailgate on a sunny day.

Generator took a dump shortly there after with a short in the armature, so I replaced it with a 10si set up for 6v +ground

Replaced all fluids, (trans fluid was gear oil and I have the hydraulics and pto option so I replaced with 20wt and did the engine oil and filter while I was at it.

Replaced the IH magneto when it died with the proper fairbanks morse model.  New mag was not properly timed and had an internal short which I repaired and retimed.  At the same time put brand new autolite 295's and copper core wires on.

Carb is a Marvel Schebler and has become almost impossible to start.  It appears from the applications I see these carbs on that it is just too large for my B, so if anyone ones where I can find a Zenith for the B that is in decent condition or preferably rebuilt already because I am getting a little burned out at this point.

Thanks for listening guys and please persuade me to keep this little tractor because my wife wants it GONE!

-Kyle

Thanks Bill! After much cranking today was able to fire it up and have it running, for a while, once running it will stay running and will restart without too much effort, I have a rebuild kit for the marvel coming this week so I may tear it down tomorrow and see if anything obvious catches my eye.  and reassemble and see if it helped if not throw in the rebuild and go from there later in the week.

With the fairbanks mag, I have timed it according to spec and it runs great but has trouble kicking off, (impulse coupler feels like it is working properly) good spark, etc.  Is it possible for the marks on the fiber gear to be off one tooth making it harder start?

Just for kicks I poured a tablespoon of gas into the carb intake and it fired right off which makes me think this has to be a carb problem.  But ether will not fire off, just puff out the exhaust.  Any ideas?  I love this tractor, when it runs it has quite a bit of power for what it is and I love it, but starting it is the big deterrent. It must be easy for my wife to start.

Like I said, I bought it to plow my driveway quicker than a snowblower can clear it so when I am at work over night (fireman) my wife can hop on fire it up with ease and plow out the driveway and proceed to work.  She is now very mechanically inclined but can follow instructions very well and loves driving it once I bust my butt starting it.

Kyle, welcome to the site. I have 7 or the little guys. When setup right, then will fire on the first or second rotation. I would guess you need a carb rebuild. If you take it apart to clean out the crud, take out the jets and orifices if they will unscrew. Blow air thru all the ports. I like to pour laqueer thinner into the bowl and let it go into the ports and set for a few minutes. Blow out with air. Better to do with the jets out if they will come, but i have done it inplace on a couple. Put a good in line filter on the line to keep the stuff out from now on. Since it runs good "after start" i would guess it is not a problme with gas suppoy or plugged gas tank line.

Thanks for the warm welcome guys, after a good nights sleep I am going to pull the carb off today and give it a thorough cleaning.  I have a rebuild kit on the way so if I need any parts they should be here by the end of the week.  After a good nights sleep I am clear headed and would not even think about getting rid of this tractor.  It is one of the most simple pieces of equipment ever designed and I'll be darned if I'm going to let it get the better of me!

I will post back with how I make out and if I can get her running and out of the barn then there will be some pictures as well.  Thanks again and post back soon.

Well. I never like to speak too soon but I believe I figured it out.

The Marvel is a TSX 154 and the choke has a flapper door on it when in the choke position.  The tractor will only run properly when 'choked'.  I used the palm choke method over the intake and it would fire to life as I would palm the choke allowing just enough air through for it to warm up then run like a dream.  There was no vacuum leak that I could find and when I would starve the carb of air completely the engine would not speed up, just stall.

To prevent using my hand to choke the tractor and have it all run properly what would be the best way to deal with this?  Modify the carb or get the proper carb?  Oh, I also tore down and cleaned all the components in the wife's kitchen sink  with some hot water and simple green.  and used some thin wire to clean out all the jets.


Edited by kwengenroth - 27 Dec 2011 at 8:10pm

I would guess you would be better off with the zenith for the B. Your venturi in the MS is probly to big to cause enough vacuum. If that is the case you can clean it till the cows come home and it will still need to be choked.  The venturi ID  needs to match the air flow thru the engine.  The venturi can be small and the only effect you will be able to tell is a lack of high end rpm's and the ability to hold the high rpm's under load.  To large and it will be hard to start and a lack of lugging power at the high end rpm's even though it will get higher rpm's. 

Try Steve. He should chime in shortly. He be the carb repairman. I have a couple but I have taken libertys with them.  Might make things worse for you. 

From the pictures, it looks like your B is much later than a 1939.  Probably at least a 1950 or newer.  The later B's often came with a Marvel Schebler carburetor.  Post back with the carburetor number so we can double check that you have the right one.  There's nothing wrong with either the MS or the Zenith when they are right.  Having said that, I'd be willing to bet that you either have a dirt problem, a choke problem, or you still have an ignition problem.  Remember that 70% of carburetion problems are ignition related! ;-)

The number on the carb is TSX 154

I really hope I do not have an ignition problem.... After paying $275 on a re-manufactured magneto I'll be pretty upset with the guy that sold it.  I am going outside to re-time the mag.  I will ignore the marks on the fiber gear and time by the fire mark on the flywheel and timing lug in the cap and go from there.  Also I will tear down the carb again, after reading some more last night I think I might have missed a couple passages as they are so small.

Thanks for the help and keep the ideas coming, I really appreciate it!!

I see the area where it says Tractor No but no number... there is and area right above it that looks ground down.... could that be it?  I will look better in the light tomorrow.  I got it running today after cleaning those couple passages out but still not as easily as I would like.  I went ahead and put a little marvel mystery oil in the remaining gallon or two of gas to run through everything.  I will let it run dry then get some fresh gas for it.

Is there any reason to run a higher octane gas to aid in starting? Avgas maybe?

Tractor # is very worn but appears to be 119903 which would make it a 1953  The guy I bought it from told me he bought it as a 1939.  Oh well...

I tore the carb back apart today, installed a rebuild kit and new gaskets.  Also took a set of old plugs and opened the gap up to just over 1/4 inch and hand cranked the tractor to insure I have good spark.  Spark is great and mag is timed per specifications.  While the carb was off I put my hand over the intake while a friend hand cranked the tractor and I had suction on all four intake strokes.  Felt like enough to get good draw into the cylinder but I do not currently have a compression tester to check that way.

The battery is currently charging so I can try to crank over and fire this baby up.  If I still have troubles I left a voicemail with Steve @ B&B in NJ and I will see what he thinks about my situation.  Slowly but surely narrowing down my problems.

Coming into this kinda late, but Brett is correct. The TSX-154 & 159 Carbs were used on the B,C, & especially the CA. I have Zenith cores on the shelf that would need to be rebuilt, if you wanted to go that way, but being that's a later model B, that could be the correct carb. Most of the early B's came with the small bore Zeniths. Brett also made a good point with the spark plugs. Plugs easily get fouled when these little engines aren't running correctly in the beginning. Once you have the timing set correctly, installing a new set of plugs can make a world of difference in the running of the engine. Many times the Mag has been the blame for a poor running engine, and here it was the plugs OR the plug wires that were the culprit. Like any other carbs, the Marvels are not excluded from the dirt factor. Always check the inlet behind the 90 degree inlet fitting. Dirt, rust and debris gets trapped in that cavity and on occasions lets trash in to play havoc with the needle and seat or gets lodged in the idle circuit. Makes you want to pull your hair out of yer' head sometimes!  If you need any more info, give us a call tomorrow. Be glad to help you out with any information, parts, or a carb if you think the one you have has been messed with to much....
Steve@B&B

UPDATE!

After Steve  walked me through the ins and outs of these simple carbs I took it all back apart and made a couple adjustments and cleaned it all again!  Then removed the tank and filled it full of bolts and shook it around to break loose the loose crud and rinsed with the 'old' gas which is now for cleaning only.  Then re-gapped and cleaned the spark plugs with some 1000 grit paper.  when reinstalling the tank and carb I cut out the middle of the hard line and put in a gravity feed filter. 

She fired right up and purred like a kitten!  Thank you everybody for all of your help!

Next is two rear wheels and tires come late winter / spring.