51 JD A carb issue

[Danny Boy]

I know this is an old story, but couldn't find a solution in searches.
I have a 51 A with DLTX-71 carb that ran/started great until last year. Started running rougher, with governor hunting then surging so I rebuilt carb and put points/plugs in late last summer. When I put it back together, it started/ran great again for a month. I'm no expert but have done the same with several of my JDs over the years.
When I took it out of the shed for spring start-up, it started, but ran real rough again. Flooding smoke and governor hunting.
Since, I have:
1) gone back through carb thoroughly and made certain all passageways are open & free. Checked float level and needle valve. Rechecked governor-throttle linkage.
2) cleaned/reset new points, installed new condenser, put in new plugs, new coil, checked wires and distributor cap.
3) plenty of hot fire in ignition to the plugs.
4) plenty of fresh gas to bowl.
Today, trying to work on it, I shut off load screw while at fast idle and it immediately quit, redid several times. I know that means idle passageway is blocked, but I drilled out with Roberts bits and blew air through everything multiple times and all appeared clear.
Any ideas?

 

[WTW]

The tractor should die if you were running at high idle and you shut down the load screw. Set Load between 3/4 and 1 turn set idle 1 1/2 turn and start it back up. With engine running wide open slowly lean / turn in load when it falters back it back out about a 1/4 turn. Adjust idle at low idle where it runs smooth. If tractor floods when idling you may have a water log float?

 

[Danny Boy]

New float & needle valve working properly.

Having reviewed all searched forum topics on late model A with DLTX-71, no suggestions/recommendations have solved my problem.
This tractor starts on first turn of flywheel with a little choke...but immediately begins hunting-flooding cycle regardless of both screw settings.
Screwing in load screw fully will shut it down at any rpm.

Very frustrating since my 4 JD G's never miss a pop over past 15 years.

 

[Pappy]

My A did the same thing when I got it. Checked the float and found it had a crack in it and would not float. Dumped the gas out and soldered the crack and no more problems.
This problem is not uncommon.

 

[NoDakInMN]

You can check float operation by removing the bowl drain and hooking up a clear plastic tube to it. When the tube is turned upright along the side of the bowl, it becomes a sight glass for fuel level in the bowl. This while either confirm or rule out the float or valve as the problem.

 

[BillinAZ]

You aren't leaking air around the gaskets at the mounting bolts, are you? Also, you might make sure there is not a short on your on/off switch or wire leading to voltage regulator/generator. Not an expert, but had similar problems once.

 

[Danny Boy]

I had checked for air leaks in carb mount bolts/gasket and also had clear intake. I thought I had plenty of hot spark all way to plugs via ign switch and wiring, but will check again.

Thanks