cant keep "D" running

[Dr. CHIP]

Im having trouble keeping my case running. I bought it last fall and over the winter I changed all the fluids and filters, , adjusted the brake pedals, and greased everything. Now the weather has broke (sort of) I got it out of the garage and drove it around a little. It starts quickly with choke out and as I gradually push choke in it runs great even under mild load (4th gear on a slope). The problem is after about 5 minutes it starts to run rough and wants to stall. When I pull the choke out it starts running good again. Then it keeps getting worse until choke is out all the way out and eventually it quits running. I have adjusted the two screws on the carb. and get no improvement. I had not drained the gas tank over the winter so I drained all the gas, rinsed tank with new gas, drained carb and installed an inline filter. I filled tank with new gas and added a bottle of Seafoam. No change. I checked the compression and all 4 cylinders were about 100. I installed 4 new plugs. Nothing has helped. I dont know how to check the timing, but it runs so good at first I dont believe its an issue. Im stumped,but hope some one here can help. sorry for the long post.

 

[rustred]

you did it all before checking the gas flow to carb. pull off line from carb if gas is not flowing a full stream then back up to the
sediment bowl and remove it and blow it all out. very common problem on all tarctors.

 

[chuck machinist]

(quoted from post at 01:02:57 04/06/23) you did it all before checking the gas flow to carb. pull off line from carb if gas is not flowing a full stream then back up to the
sediment bowl and remove it and blow it all out. very common problem on all tarctors.

Inline filters may not allow fuel flow sufficiently. Check fuel flow with inline filter. remove inline filter and check fuel flow again. Carb may have certain passages plugged also. Thorough cleaning of carb passages is a must. Keep us updated on your progress.CM

 

[Russ from MN]

First thing to try is to take the drain plug out of the carb and make sure you have a steady stream of gas
out of it. Since Old isn't hear I will mention that! It could also be a bad coil or condenser.

 

[rustred]

you will not have a steady stream of gas out of it. if your removing the plug from carb the gas will run out full flow for about 3 seconds then it will trickle out at the same rate it is running into the carb past the needle and seat through a 1/16 inch hole. that is why i always remove the line from the carb it is a way more accurate test. then you remove the carb plug and run some gas out to flush the junk out. so why do it any different? the sediment bowl outlet can be half plugged and you will never know it just draining gas out from the carb.

 

[Tgrasher]

When cleaning/going over the carburetor
pay special attention to the cavity
leading to the needle valve from the fuel
line. A flake of dirt/rust at this point
will reduce flow enough to cause your
problem.

 

[Dr. CHIP]

Despite my wordy post I neglected to mention fuel flow to carb. The tractor ran this way before I did anything. I did install a more accessible fuel shut off because if I didnt shut it off the fuel would run out of the carb when not running. It runs out the center of the bowl from??. When I drained carb fuel ran out readily. I Did remove and clean sediment bow, it looked clean. The previous owner told me the carb had been rebuilt. My next step is to have it "rebuilt again. Im pretty sure its a fuel problem because of the response of the choke, but I dont know why it goes from running great to not after it warms up. I havent done anything to the coil or other ignition stuff. Im not experienced in rebuilding carbs but I have a friend who specialises in rebuilding old engines.
I might also add that it has been converted to 12 volt with a resistor installed before coil. The generator appears not working so Ive been runnind it with a jumper box attatched to battery

This post was edited by Dr. CHIP on 04/06/2023 at 02:23 am.

 

[VAC400]

Dr. I what you to take off your fuel cap and check the flow to the carb at the inlet. there are times
when the vent hole is plugged .
But to check first leave the cap on and see if you have a go flow if not remove the cap and see. This
happens to older tractors even newer ones. It happen to a parade tractor at my friend had , so I took
one off of my tractor and put it on. If that is ok than let me know and I will tell you what to check
next.

 

[Don Rudolph]

If your carb issues are solved and it still runs like this, a weak coil can mimic these symptoms.

 

[Russ from MN]

I prefer to take the bowl drain out, as I remember that's what Old recommended. That proves that gas is getting through the inlet filter and past the needle and seat, all possible restrictions. I know it might not be a large stream, but it has to be enough to run the engine at WOT.

 

[used red MN]

OK, letting you in on a dirty little secret for those who
are not ..old hands.. at working on old tractors. I am
not that familiar with the Case D tractors, but many old
tractors had the following. Where the line from the fuel
tank connects to the carb, the fitting it screws in may
have a fine screen in it. This is why checking the fuel
flow out of the carb drain is the best approach,
especially for those less seasoned in mechanical
knowledge. I will attach a link to an example of this
item. See if you have one take it out and clean it if it is
clogged most likely this is your problem. Depending on
the configuration the fitting and screen may be
straight and not an elbow.
Carb inlet fuel strainer

 

[Mike Fitz]

An easy thing to check is if there is something floating loose in the gas tank that can stop fuel flow after it has run a while, I had that happen with my 730 there was a large bug wing in the tank and it would float over the outlet and stop the tractor, it was
translucent and hard to see. Mike

 

[Dr. CHIP]

I took gas cap out and took drain completely out and got a good stream of gas running out. I took a video of it but I cant see how to post it. Next step I guess order a new coil.

 

[used red MN]

To clarify the drain you took out was in the bottom of
the carburetor? I am just asking because comments
were made about junk in the tank blocking the outlet.
Just making sure the word drain was not being applied
to the sediment bowl base is the tank. A lack of proper
fuel flow to the carb is a very common problem. The
failure of a coil, as Don R.mentions happens but it is
fairly rare. Another thing that may mess up the ignition
in a similar way is bad condenser. My experience with
them has been that do not take long to fail, often in the
first minute or two.

 

[Dr. CHIP]

yes- bottom of carb

 

[rustred]

yes i realize that but what i am saying is the sediment bowl inlet can be half plugged and you will not know it by trickling the gas out the carb.. first is to remove the line then watch for a full fast stream of gas depending on how much in the tank. the fuller the tank the farther the stream , as if you drank 6 beer and waited 2 hrs. lol.

 

[C.Amick]

I'm guessing it's the coil that is the problem. Have you changed out any ignition parts? Most new China made parts are junk including coils and condensers.

 

[Dr. CHIP]

(reply to post at 04:33:37 04/09/23)

I havent changed any ignition parts. I have a 6volt coil with a ballast resistor ahead of it. Should I replace it with a 6v or 12v? Same with condenser?

 

[Dr. CHIP]

maybe the easiest solution is go back to 6 volt

 

[Dr. CHIP]

Well its been awhile but finally got back to the case. I got a new coil installed and nothing has changed. Got a new condenser but havent installed it. Im gonna pull carb and have that gone through.