1963 4000 will not run unless choke is all the way out

ranchhopper

New User
I am having a problem with my neighbors 1963 ford 4000 it will not run unless the choke is all the way out. It will start with the choke off but will not accelerate with out it being pulled all the way out. I just installed a newly rebuilt carb on it I pulled the air cleaner oil bath reservoir and found it full of ice so I left it off the air cleaner while I worked on it and while I had it running it made no difference in the way it ran. I refilled the reservoir with new oil so now back to the drawing board. I work on diesels in my pick ups and mack trucks so carbs are a new thing for me any help would be appreciated.
 
Fuel delivery weak I'd say. Choke is reducing the air inlet available for the amount of fuel available. Clogged fuel line, tank strainer, got a
glass bowl on the filter? If so, does it stay full or does the level drop down when accelerating, strainer varnished up, bad fuel......way out
SWAG......timing retarded too far.
 

I have a Ford 961, which is nearly the same tractor, and they both usually have the same Marvel Schebler carburetor. Needing the choke to run usually means one of three things: lack of gas to the carburetor, low level of gas in the float bowl due to the float not set correctly, or a blocked main jet passage. Since the carburetor is freshly rebuilt we hope to not have to suspect it. The easiest thing to check is adequate flow of gas to the carb. To check it make provision to catch the gas from the bottom of the carburetor in something like a coffee can. shut the gas off at the tank then remove the drain at the bottom of the bowl. Then turn the gas back on and observe the flow for at least a full minute. It needs to keep flowing a steady stream strong enough to flow approx. a pint in a minute. See what you get then post back.
 
Its my neighbors tractor she is 75 years old with a lazy son in law who wants her to buy a skid steer to unload hay for her horses which is what this tractor is used for. He will not maintain it because he wants her to get rid of it so myself and a friend try to keep it running for her as she doesn't have the funds for a skid steer. I sent the carb in for the rebuild I cleaned out the sediment bowl and screen and installed a filter in line to keep the carb from getting any rust and crap in it again. I will check the fuel flow tomorrow thanks for the help.
 
I think if it were mine I would shut the fuel off then take the fuel line loose at the carb and open the fuel valve and see how much fuel you get. drain the line into a gas container. If you have an air tan blow back up through the line. You might have a restriction in your line. if it starts fine but wont run if you give it the gas then you have a restriction some where. pulling the choke puts more vacuum on your carb to put more fuel but it also limits the air intake which will cause fuel rich mode indicated by the black smoke coming from your exhaust.
 
Most carburetor problems are in the ignition. Poor spark can cause exactly the symptoms you describe, since an over rich mixture is easier to ignite than a normal mixture.

Far as I can tell, I agree with all the fuel based possibilities everyone has suggested. But I would verify spark first. Poor spark is usually caused by bad connections, bad wires, pitted or corroded points, dirty plugs, or a bad condenser.

If the fuel delivery/carburetor remedies already suggested don't help, and you wish to move on to ignition, please re-post. One of the cows just had twins, and I'm not inclined to type more than I have to between trips to the barn tonight.

Zeke B.
 
Ran crappy then too I never got out there to work on it tomorrow I'm going to pull the plugs an give them a look see.
 
installed a filter in line to keep the carb from getting any rust and crap in it again.

The inline filter may be tripping you up.

TexasMark & Showcrop gave you very good troubleshooting advice.

With fuel valve off, remove the float bowl drain plug from the bottom of the carburetor then open the tank valve and allow it to flow for 30 seconds. You want to drain the float bowl to evaluate fuel flow through all of the screens and filters.

will not run unless the choke is all the way out. How did it run before carb overhaul? Ran crappy then too I never got out there to work on it

Did it need full choke to run? I'm trying to determine if carb overhaul contributed to run problems. Idle mixture (not idle speed) and pilot jet should be turned 1½ turns off of seat as an initial setting. Once tractor is warmed up then make final adjustments.
 
I went out yesterday and checked out the plugs they were clean but smelled heavily of unburnt gas gaps were good. I pulled the distributor cap it was clean no corroded contact points I think I may have a timing problem. The tractor will not start unless the throttle is all the way down to idle position will not even fire on ether usually that's a good way to tell if its getting fuel. It wont even pop on ether so either it has no spark or its so out of time its not firing at the right time.
 
The tractor will not start unless the throttle is all the way down to idle position will not even fire on ether

I am not chiding you but please understand that when trying to diagnose a problem over the internet, we rely heavily on posters response and whether they are following the troubleshooting advice.

The above post indicates it will start (run) at idle but it won't fire with ether? Those two are mutually exclusive.

What were the results of fuel flow test? [b:26823965d3][i:26823965d3]"With fuel valve off, remove the float bowl drain plug from the bottom of the carburetor then open the tank valve and allow it to flow for 30 seconds. You want to drain the float bowl to evaluate fuel flow through all of the screens and filters"[/i:26823965d3][/b:26823965d3]

Inline filters are notorious for not passing enough fuel unless it specifically states for gravity flow applications and these 172s are very thirsty.

To satisfy ignition system concerns, pull number one spark plug wire. Insert any known good spark plug that is gapped to 3/16". Ground the plug and try to start it. If it fires, your ignition system is intact.

I don't think this is your problem but post back and I will help you verify distributor timing.
 
I can see the post I put on her would cause a bit of confusion. I should have stated it did fire up only with the throttle at idle position but now is probably flooded and will not start at all now not even on ether. I am confused why it wont fire with ether though if it was a fuel problem it would have run on ether even without gasoline. This is why it makes me wonder about it being a timing problem because it should run on ether. I will check to see if the spark is good which if I were a mechanic would have checked first but didn't because it did run just not very well.
 
Got the tractor started today only starts at idle position but runs all the way up to full throttle has to stay choked though. It will start to backfire if the choke is pushed in even a little pretty strange.
 
Got the tractor started today only starts at idle position but runs all the way up to full throttle has to stay choked though. It will start to backfire if the choke is pushed in even a little pretty strange.

It isn't strange at all. The symptoms described above are classic indicators of the incorrect amount of fuel being delivered usually caused by clogged fuel supply, wrong type of inline filter, or trash in carburetor.
 
(quoted from post at 20:12:47 12/18/17) Got the tractor started today only starts at idle position but runs all the way up to full throttle has to stay choked though. It will start to backfire if the choke is pushed in even a little pretty strange.

Ranchhopper, your problem is actually your refusal to take the suggestions being offered.
 
I am slowly going through this thing and I have all the suggestions written down and try to go through them as I go. I'm not ignoring any suggestions I checked fuel flow and its good the inline filter is full of fuel fuel flows good as someone suggested take the line off and check I did that. Its hard to believe but not unlikely the carb could have problems as I took it out of the box and installed it made sure there was no crap in the fuel line and installed the filter before running fuel to the carb just in case I didn't get all the rust and other things out. Site glass shows no water in fuel I'm slowly going through it as I have time and I do appreciate all suggestions and I'm not ignoring them sorry if it appears that way.
 

If it were me, I would remove the float bowl drain plug on the bottom of the carb. This confirms fuel supply integrity end-to-end.
 
Its hard to believe but not unlikely the carb could have problems as I took it out of the box and installed it made sure there was no crap in the fuel line and installed the filter before running fuel to the carb just in case I didn't get all the rust and other things out.

I wouldn't be too quick to rule out a faulty carb seeing the number of posts with repop carbs problems.

If you determine fuel flow through the float jet is adequate, next item to eliminate would be float level. Should be 1/4" between bottom of float and carb housing with bowl gasket in place.

Initial setting should be 1½ turn out on the side pointing idle/air adj. screw, and 1½ turns out for the main fuel needle. Start at idle speed (450-500 RPM) and let the engine warm up to operating temp then, adjust the idle air screw, in to get the highest smooth idle 1/8th turn at a time and listen for highest RPM. After you set the engine running at idle, then you can set the main jet for max fuel needed to run at WOT under load.

Keep in mind, the idle jet needle on an M-S TSX carb is an air control needle so tuning it in enriches the idle mixture whereas the power jet needle turning it in leans the mixture.

mvphoto7852.jpg


As you are helping out a neighbor, send me the OEM carb you removed and I will be glad to rebuild it (Email open in Modern View for address).
 
(quoted from post at 02:29:05 12/20/17)
Its hard to believe but not unlikely the carb could have problems as I took it out of the box and installed it made sure there was no crap in the fuel line and installed the filter before running fuel to the carb just in case I didn't get all the rust and other things out.

I wouldn't be too quick to rule out a faulty carb seeing the number of posts with repop carbs problems.

If you determine fuel flow through the float jet is adequate, next item to eliminate would be float level. Should be 1/4" between bottom of float and carb housing with bowl gasket in place.
Yesterdays tractors didn't have a replacement for the schebler that was on it so I had to send the carb that was on the tractor down to ohio where they get their carbs rebuilt. I didn't want to buy an aftermarket and we were not in a hurry to get it back that's why I did it this way.
Initial setting should be 1½ turn out on the side pointing idle/air adj. screw, and 1½ turns out for the main fuel needle. Start at idle speed (450-500 RPM) and let the engine warm up to operating temp then, adjust the idle air screw, in to get the highest smooth idle 1/8th turn at a time and listen for highest RPM. After you set the engine running at idle, then you can set the main jet for max fuel needed to run at WOT under load.

Keep in mind, the idle jet needle on an M-S TSX carb is an air control needle so tuning it in enriches the idle mixture whereas the power jet needle turning it in leans the mixture.

mvphoto7852.jpg


As you are helping out a neighbor, send me the OEM carb you removed and I will be glad to rebuild it (Email open in Modern View for address).
 

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