new to the group and need a bit of help

[robbo1961]

Hi Folks - thanks for the add. I bought a Farmall Cub with numerous attachments this summer, but I have been having quite the time keeping it running consistently. It seemed to run fine when I got, although carb float stuck (i.e.) didn't close, so fuel would just run out of the carb if the bowl valve was not shut. I pulled the carb apart, but one of the brass pieces broke. So I bought a new carb on-line, but still had issues with the needle valve not closing. I messed with float setting for the better part of 2 days and finally gave up. I contacted the place where I bought the carb and they sent me a new one. Still the same issue. I was tired of chasing my tail on that issue and needed to use the tractor, so I just went back to closing the bowl valve when the tractor was not running. I never could get it to run consistently and reliably.

My situation now is that the tractor starts fine (when choked) but takes a long time to warm up. When it does, I can back off the choke and it idles very smooth, with exhaust not being too smokey (for an old tractor). However, when I try run it around, it sputters after a bit and quits. I usually can get it started again, but have to choke it, even when warm. Eventually I can bake the choke off again and it idles just fine, but stalls when I try to move it. Sometimes it acts like its not getting enough fuel (i.e. the choking when warmed up) and other time it seems to flood out, with gas pouring out of the drain on the carb. Here is what I have tried so far

-Cleaned out the fuel tank and bowl, and added an inline filter.
-filled the tank with premium gas and added a can of Seafoam for good measure.
-Checked the air filter system and the oil there seemed just fine (i.e. no obvious signs of water).
-Played with the mixture settings - it seems to run fine at 1 1/2 turns out up to 3 turns out.
-Changed out the spark plugs.

My next step was going to be to check the float setting on the carb, even though it is suppose to be set correctly right out of the box. Before I do that, I thought I would check in with you folks. Does anybody have any suggestions?

Thanks in advance

Rob

[Bob McCarty]

Rob, Welcome to the Forum. The brass piece that broke was probably the idle tube. The broken pieces can be removed and the idle tube replaced (4-48 tap). The tractor should still run okay that way. If the new carb you got is one of the repros from China, the float probably isn't set correctly. The viton needles can also stick or leak. If resetting the float doesn't help, make sure the filter you've installed is for a gravity fed fuel system and not for a fuel pump system. Although your symptoms sure sound like a fuel problem, you may want to check/change the points and condenser. There have recently been several threads like yours that turned out to be electrical related rather than fuel.

[Eugene]

Welcome.

If you haven't done so, conduct a 100% engine tune up. That includes compression tests, valve tappet clearance, ignition, in addition to your fuel problem.

Start with the compression tests. These tests will provide a good indication of your engine's condition.

[inairam]

I am not a fan of the inline filter. I think they tend to be a fuel restriction and the bowl and screen under the tanks work fine when clean and in good repair.

It does sound like a fuel restriction. I would drain the tank and remove the bowl valve assembly, clean it, inspect it and replace the screen and check the fuel line for clogs or dents or anything else that could cause a restriction. Inspect the inlet screen of the carb for debris. They tend to get damaged when people put in the file line. I would also do what Eugene suggests and adjust the values and timing.

I also would remove the air intake cap and the oil bath cup and look in for restriction like a nest of some sort. I can not tell from your description if you changed the oil in the bath. If you did not do it. There could be a lot of crud and water on the bottom that especially in cold weather will restrict the air flow. Remember the water and crud is on the bottom of the cup and not obvious from looking at the top of the oil level in the cup. I have pulled ice donuts out of the cup.

Maybe try to rebuild the carb you have instead of buying a new one. A number of members recommend McDonald Carb for kits and parts http://www.mcdonaldcarb.com/category_s/388.htm.

You should start at 1 1/2 turns on the mixture and advance the throttle. If it is stumbles when you advance the throttle keep adjusting it and out. 3 turns out sounds like a lot to me.

[Mrblanche]

The aftermarket carb I just installed came with the float set extremely low. If I recall my Auto Mechanics 101, that would have caused exactly the symptoms you describe.

[staninlowerAL]

In addition to the full tuneup, also check the fuel flow at the carb to determine if there is any restriction in the tank/outlet shutoff valve/screen. The stream should be about the size of a pencil and flow freely without slowing down for as long as the valve at the tank is open. The main jet is another place to check by removing it and check each opening with a small soft wire, about 22 ga. Don't enlarge the holes when cleaning. Spray with carb cleaner and blow out with air pressure.

[Glen]

Hi,
They have said on here before that to use an inline gas filter on a Cub, it has to be for a gravity flow fuel system, so the gas will flow fast enough through the filter.

You didn't say what year Cub you have, or if it has a Magneto, or a Battery Ignition unit. Cubs have ignition points, like cars years ago did. They need replacing regularly, so the engine will start good, and run good.
The ignition timing should be set correctly, so the engine has good power.

Below are pages from the 1955 Cub owner's manual, showing servicing the points in both types of ignition. The 2 units are different, but use the same points and condenser.
The pages also show how to time a magneto to the engine.
The Battery Ignition unit is timed using a timing light.

http://farmallcub.com/rudi_cub/www.clea ... e%2038.jpg

http://farmallcub.com/rudi_cub/www.clea ... e%2039.jpg

http://farmallcub.com/rudi_cub/www.clea ... e%2040.jpg

http://farmallcub.com/rudi_cub/www.clea ... e%2041.jpg

http://farmallcub.com/rudi_cub/www.clea ... e%2042.jpg

Below is a listing for new points and condenser at TM Tractor, you can look at.

http://www.tmtractor.com/new/el/367fp.htm

Below is a page from the Cub service manual, showing the float level, and float drop for the IH carburetor, in the upper pics. It should be set to exactly the specs shown.
To set it, the top half has to be removed from the carb, and turned upside down, like the pic of the Zenith carb, on the lower right of the page.
You need a measure with 32nds of an inch markings.

http://www.farmallcub.info/manuals/gss- ... 002-09.jpg

The IH carb float level is measured without the gasket between the halves in place.

[staninlowerAL]

Rob, after your second post you can access and download any of the manuals at the Quick links tab, top left corner of this page. Select pdf manuals, then select the manuals that you would like to view/download. Good luck with your project.

[Don McCombs]

[robbo1961]

Thanks for all the responses and suggestions - this seems like a really great and supportive group!

Sounds like I should shore-up the fuel issues first and if I can keep the tractor running, work on the tune up (or hire that out if I can find someone locally). After I departed with my 1971 Pontiac Venture some years ago, I ditched my timing light and diagnosis equipment. Now that I own the Cub and a Ford 8N, it might be time to acquire that equipment again.

In any case, I will report back. I'm still getting a feel for how the old posts are organized, so I apologize in advance if I ask a question that is a repeat.

Rob

[Dale Finch]

If you haven't already found it, there is a great collection of posts for various common issues, sorted by subject area, under BOARD INDEX > HOW TOS. They are worth the time to read through!

If you get stuck, just ask...these guys (and gals!) are like little puppies being offered doggie treats..."call on me...I know the answer!!"

[Smokeycub]

The others are giving you plenty of great advise. My $.02 - I noticed you changed the spark plugs. Was there any improvement? If so did it run better for any length of time? To me at least, your symptoms sound very much like weak or fouled plugs. There are a number of heat ranges available for the Cub and if you have a set of plugs that are too cold they'll foul pretty quickly. I would recommend Champion D21 or the equivalent, depending on how hard you work your tractor. ...and for what it's worth the plug wires need to be copper core not resistance wires.