Allis B runs a while then quits

I rebuilt the Marvel carb because the B kept stalling on me when I put only a light load on her. Got to the point even letting out on the clutch nice and slow would cause her to stall. Now that I've rebuilt the carb, she runs good for 15 minutes or so then the same thing happens, she starts missing stalls out. I've tried giving her some choke when she does it thinking she is running lean but it does not seem to help and she quits anyway.

I'm starting to wonder what is going on and thought it was the carb but maybe not. Next I'm going to put the old, non rubber tipped needle valve back in and try it again in case it's sticking and if that does not work I'll try re-adjusting the float. I set it as instructed at 1/4" from the gasket but maybe it needs to be 3/8" or so. All fuel lines have been changed and have added a filter along with using the original fuel sump. I've cleaned, soaked and brushed every part of the Marvel carb and feel pretty sure I've done all I can to be sure I have missed nothing there.. I will keep trying until I figure it out and then move on to spark plugs, wires, points, condenser etc.

Any ideas other may have to share that might point me in the right direction would be greatly appreciated.

RSouth,
Sounds like a fuel deliver issue.  I think you've covered everything that I would look at.  One more thing though...make sure there isn't air blocking the flow of fuel to the carb.  This happens to me.  I always open the petcock on the carb bowl, then open the fuel tank petcock.  Once fuel is coming out the carb, I close it off.  This method establishes an unbroken fuel supply to the carb.  Good luck.  Let us know what the problem was.

Mag coil

Next time it quits, pull a plug wire from a plug and hold the metal end a quarter to 1/2" from the head or block, anything ground and crank it. There should be at least a quarter inch, preferably a half inch blue spark in air. There is a chance you will get bit through the wire insulation too. Make that check before running it too, to learn how much spark it should have.

Its possible the condenser is the problem not the coil, and its cheaper to replace when replacing parts is the only test possibility.

Gerald J.

The first thing I would do is to remove the fuel line from the carburetor and drain a gallon of gas out thru the gas line.  I have had more problems with crap in the neck of the sediment bowl than coils.   

Just my 2 cents.  I had similar problems with my D17 over the course of the last year.  I could get it to idle fine but put any load on her and she would start acting up.  I started on the fuel/air side and replaced/rebuild manifold & carb, replaced fuel line fittings and strainer.  All the while replacing cheap points and condensers on a frequent basis.  What finally made the difference?  Pertronix.  It's like a new beast.  Seriously.  If I would have started there first I could have saved myself a lot of trouble.  On the bright side, I got a lot of other things lined out along the way :)


Edited by dirtfarmer - 06 Dec 2015 at 8:21am

Hello R South    I agree with Dick except open the plug under the carb, it should run a solid stream for a while, If not put a fine screen shaped like a cigarette in the fitting that screws into the tank. Good luck

RSouth,  Where are you in Maryland?  Since it is not too big a state you cannot be too far away.  Love to meet another Maryland man.

Edited by Bill Long - 07 Dec 2015 at 8:18pm

Dump 5 gallons of gas in the tank and then put a pail under the carb bowl drain.  Use a funnel and then open the drain.  If all 5 gallons comes out with no problem, you have an ignition problem.  I'd go with a new (USA made) condenser first and then a coil.  Go to NAPA...  I would lean more toward ignition I think, but check the gas first.  That is the easiest to do.

believe dave has it figured out,especially if you have a magneto.if you have a mag.dont use carbon wires on the plugs,copper wire only.....

B-B Custom Circuits in New Jersey. Steve is a sponsor.

Electrons are smaller than even hydrogen molecules that are the smallest molecules. So it doesn't take much of a hole for high voltage electrons to sneak out.

Gerald J.

Rsouth iam in Salisbury you need any part give me call got several b s in the parts yard sent you pm with contract

I had one do this a yr ago did all I could do to get it fixed . I then was at a friends shop one night and ask him what it could be . He said did u put new plugs in I said no it run good y . He said I had a truck do it to me when it go hot the plugs would jump from the plug the the head and it would miss and stop . Isay OK how u fine this at drak u could see it I put new plus in and run great . Just my two cents .