Bought a new Cub today

[Waif]

Bear with me. Only what I'd run through myself.

When it quits with the symptom of no fuel left in the carb , is the carb really dry/empty? Pulling the plug right away would be telling. If it is dry , recheck gravity flow and venting of fuel.

Another symptom is it dying when choke is moved to off. What position is the actual choke plate in when you have it in "off" position?
I ask because I've had the choke lever on the engine side of carb move more than once, and was choking the carb when I thought I was turning choke off. It was easier to recognize the second time. l.o.l.
A burr on the clamp was making the screw feel seated tight when it wasn't.

Is the air intake system clear? As well as valves functioning ? It's not huge vacuum but it matters she's breathing.
One tractor came home with a very strange (and dense) goop of oily insects in the oil cup of the air intake. That led to cleaning top to bottom. The intake screen might have had mud daubers working it , the screen was pretty filled in. Flush with screen though , so someone previously might have cleaned the worst of it off the outside.(?)

[Jim Becker]

Needle valve sticking.
Any of the 3 screens needs cleaning.
Obstructed passage from tank into sediment bowl.
Obstructed fuel line.

Start with any of these you haven't check yet, then return to the ones you have.

[k hutchins]

Ok, before reattaching the carb l checked the flow on the line by openning the shut off. All great. So tank screen, sediment bowl, and line are clear.
I double double checked the air cleaner, no problem there. I reattached the carb with the exception of the air hose and attempted a start. Got nothing until l pulled the plug on the bottom of the carb to verify l've got gas. Secured it back in place, choked, crank. It started, choke off, ran for 20-30 seconds and died. Pulled the plug at that point after shutting off gas. The bowl was empty.
I believe the float maybe touching inside the bowl when assembled. I'm not sure how to verify this since it drops when you seperate the top and bottom. Should l be able to hear it when l turn it over? Or maybe incerting something through the plug hole to verify it's moving freely.
I'm scratching my head wishing it was made out of glass so l could see what's happening.

[indy61]

I believe the float maybe touching inside the bowl when assembled. I'm not sure how to verify this since it drops when you seperate the top and bottom. Should l be able to hear it when l turn it over?

Yes you should be able to hear the float moving by turning the carb upside down and back.

[Eugene]

Check to see if one side of the fuel bowl is bent in a bit.

[Jim Becker]

Did you check the screen where the fuel line attaches to the carburetor?

[Don McCombs]

There are two situations where manipulating the choke will change performance. Insufficient fuel and too much air. Sounds like you’ve investigated the insufficient fuel fairly thoroughly. To check for too much air, look for a loose or cracked manifold, or a missing or cracked manifold or carb intake flange gasket.

[k hutchins]

I may have discovered my problem.

Bottom of bowl to edge 1 9/16

Edge to bottom of float 1 7/8

By my calculations even with a 1/16 thick gasket when not compressed. The float is hitting the bottom of the bowl and pushing up at least an 1/8 of an inch. That's a lot when you consider it's only supposed to move 3/16 to open and close the needle valve.

Now the hard part. Remedies?

[Bob McCarty]

In your second photo you say you have the float drop at 1 7/8" (looks like 2" on the tape). The drop should only be 1.6", not 1.88". Looks like it's dropping over 1/4" too much. What is the float height now?

[k hutchins]

The pic was a poor angle, it actually measured 1 7/8-1 15/16 to the bottom of the bowl from the top frame. The bowl is only 1 9/16 deep. So by my calculations it's hitting the bottom of the bowl and pushing up far enough to close the needle.
Studying the closer, l believe the float is upside down. If l turned it over, reversed the tab, and adjusted the drop. I believe it would be centered in the bowl instead of haning it so low it hits the bottom and pushes up.

[Bob McCarty]

I'd suggest resetting the float height and drop to the correct numbers. See if the problem persists. I've not heard of a float having the tab bent backwards, and I think you'd break it off if you try that. The needle doesn't need to move much to allow gas to enter the bowl.

[ctltmp]

In your second photo you say you have the float drop at 1 7/8" (looks like 2" on the tape). The drop should only be 1.6", not 1.88". Looks like it's dropping over 1/4" too much. What is the float height now?

Bob's numbers are correct for float adjustment. When the carburetor is inverted (float in up position) the measurement should be 1.4". When the float is in the down position (drop). Should be 1.6".

[Don McCombs]

Studying the closer, l believe the float is upside down.

Before you do anything to the float, post a photo of it uninstalled. Just the float.

[Glen]

Hi,
Below is a listing for a new float at TM Tractor, the tab on the float has to face up.
Then the tab hits the side of the seat when the float goes down.
You can look at the pic on the left in the listing, and see if your float is the same.

http://www.tmtractor.com/new/fl/655fp.htm

Below is a page from the Cub service manual showing the float and the tab, in the upper left pic.
The lower 2 pics are for a Zenith carburetor, disregard those, except that the IH carb float level is set in the same way as the pic in the lower right of the page, the top half of the carb off of the bottom half, and upside down, with the float in place.
Use the specs for an IH carb, if you have an IH carb.
Also, the float level on the IH carb is set without the gasket in place.

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

[k hutchins]

Float at full drop

Float at full rise

Hey guys, thanks for the input.
After sleeping on it lastnight, instead of reversing the tab and turning the float over. I think I can just bend it up on it's "arm". Looking at how much space there is between the top of the float and the body of the carb when it's up, l think I can bend it at the connection (carefully) so it won't hit the top and won't drop so far to hit the bottom when assembled. If l don't change the tab, l should still get my 3/16 drop to open the needle.