John Deere 1010 carburetor problem

[[email protected]]

This tractor has a Marvel Schebler carburetor, identical to its twin that I also have. On this tractor, operating the choke lever has no effect on engine behavior. Totally different on my other 1010. I am pretty sure that when operating the control the butterfly valve at the air intake operates as expected, but there is no change in engine behavior. This tractor is very hard to start from cold but otherwise runs fine and starts fine after first start of the day. It behaves as if it is not being choked when cold but to the eye it appears to be.

 

[Janicholson]

Welcome to YT forums and PartsASAP
With the intake from the air cleaner removed, you should be able to see the choke butterfly. A piece of paper about as wide as a stick of gum can be placed in the path of the butterfly. close the choke and see if it has been captured (pinched) by the butterfly. If so, look carefully at the butterfly plate to see if it has a relief valve/spring in the plate. if this small disc is missing, or the light spring that holds it shut is missing that will also cause lean starts. Jim

 

[wore out]

This tractor has a Marvel Schebler carburetor, identical to its twin that I also have. On this tractor, operating the choke lever has no effect on engine behavior. Totally different on my other 1010. I am pretty sure that when operating the control the butterfly valve at the air intake operates as expected, but there is no change in engine behavior. This tractor is very hard to start from cold but otherwise runs fine and starts fine after first start of the day. It behaves as if it is not being choked when cold but to the eye it appears to be.

IIRC, there's a "relief poppet" in the choke plate, if this is missing or damaged it would explain the hard starting, but I'd still expect pulling the choke to have some effect on the engine when running.

 

[[email protected]]

Welcome to YT forums and PartsASAP
With the intake from the air cleaner removed, you should be able to see the choke butterfly. A piece of paper about as wide as a stick of gum can be placed in the path of the butterfly. close the choke and see if it has been captured (pinched) by the butterfly. If so, look carefully at the butterfly plate to see if it has a relief valve/spring in the plate. if this small disc is missing, or the light spring that holds it shut is missing that will also cause lean starts. Jim

I took a look at the exposed choke in both the tractor that starts hard cold as well as the good one. The pinched-paper test worked fine on the bad tractor, and that little relief plate inserted in the butterfly is indeed present, is spring-loaded such that it returns to closed position but can be pushed open. This is the same on the 'good' tractor except that relief plate seems to move with less resistance and return to closed more readily than the 'good' tractor. I have attached two photos for comparison, although it is difficult to get a good picture. The 'bad' tractor had not been started since last September so I expected a challenge today. When I tried starting it with the choke out I got the normal hard start. However, I decided to manually 'choke' the air intake by removing the cover and blocking the tube with my hand. The tractor started immediately upon cranking. I am really mystified here as it is clearly a lean start problem but for the life of me the 'bad' tractor choke seems to be operating fine.

 

[[email protected]]

IIRC, there's a "relief poppet" in the choke plate, if this is missing or damaged it would explain the hard starting, but I'd still expect pulling the choke to have some effect on the engine when running.

I just posted the results of my test/inspection today to the previous comment. Can you see that as well as the pictures I included?

 

[wore out]

I just posted the results of my test/inspection today to the previous comment. Can you see that as well as the pictures I included?

Yep, your photos came through. Dunno what to add other than you've now seen the details of how the choke plate works.

A possible intake leak, float level differences, jet differences, or even the general condition of the engine COULD be factors here.

 

[rustred]

I took a look at the exposed choke in both the tractor that starts hard cold as well as the good one. The pinched-paper test worked fine on the bad tractor, and that little relief plate inserted in the butterfly is indeed present, is spring-loaded such that it returns to closed position but can be pushed open. This is the same on the 'good' tractor except that relief plate seems to move with less resistance and return to closed more readily than the 'good' tractor. I have attached two photos for comparison, although it is difficult to get a good picture. The 'bad' tractor had not been started since last September so I expected a challenge today. When I tried starting it with the choke out I got the normal hard start. However, I decided to manually 'choke' the air intake by removing the cover and blocking the tube with my hand. The tractor started immediately upon cranking. I am really mystified here as it is clearly a lean start problem but for the life of me the 'bad' tractor choke seems to be operating fine.

Well
The choke is not closing completely as that’s what I see in the above photo. Not gonna start good like that. Get the choke adjusted properly.

 

[wore out]

Well
The choke is not closing completely as that’s what I see in the above photo. Not gonna start good like that. Get the choke adjusted properly.

If I'm looking at his photos correctly the tractor that starts "good" has the "loose" choke, WTH?

 

[rustred]

If I'm looking at his photos correctly the tractor that starts "good" has the "loose" choke, WTH?

If he would separate them photos and tell us which is which would help a lot. Ya now I see it says good tractor with loose choke in the photo. Who knows.

 

[Fixingfarmer]

so correct me if I'm wrong but the relief plate on the good one returns easier? id probably start there new choke plate. or even switch the carbs quick see if it moves to the other tractor that's the best thing about twins.

Id be tempted to try a plate without a relief if one exists or make your own but that's just me

I also assume that the notch in the top of the intake (horn I believe?) of the carb is there on both we just can only see it in the one photo?

 

[[email protected]]

If he would separate them photos and tell us which is which would help a lot. Ya now I see it says good tractor with loose choke in the photo. Who knows.

You are correct. The one that starts well is the one without the choke totally closed. I had that same question myself but there is zero doubt about that. The photos are labelled correctly. I assume that you would want the choke fully closed when the knob is fully pulled out so the 'good' tractor is not properly adjusted, yes, but starts fine from dead cold after 7 months.

 

[[email protected]]

If I'm looking at his photos correctly the tractor that starts "good" has the "loose" choke, WTH?

I also believe that the 'good' tractor photo is slightly misleading as the angle of the photo is lower than the throat of the intake and makes it look like the butterfly is more open than it is. When I manually inspected the 'good' tractor butterfly valve it looked quite closed with the knob fully out.

 

[[email protected]]

so correct me if I'm wrong but the relief plate on the good one returns easier? id probably start there new choke plate. or even switch the carbs quick see if it moves to the other tractor that's the best thing about twins.

Id be tempted to try a plate without a relief if one exists or make your own but that's just me

I also assume that the notch in the top of the intake (horn I believe?) of the carb is there on both we just can only see it in the one photo?

Yes, I will consider just swapping carbs and see if the problem moves and if so I will do a rebuild kit on the bad one or just buy another carburetor once that is proved. I appreciate all the advice and comments. To answer your question, it is the relief plate on the 'bad' tractor that seems to move and return to closed position more easily. When I push the relief valve on the 'good' tractor open it seems to stay partly open, whereas it flips closed right away once I remove my pressure on the 'bad' one. Like I said, though, when I manually via my hand choked the 'bad' tractor it started immediately so it sure seems like a problem with the choke.

 

[Fixingfarmer]

The only other thing would be like wore out said above intake leak somewhere along the way.

Use fresh gaskets during the swap

You have proven it starts and runs with your hand so fuel and electrical are probably ok

A quick check spraying the intake all over with ether carefully see if the speed increases once it’s running is often how I verify there isn’t a leak. Everything has to be closed up. We don’t care much about stuff behind the carb air cleaner all the way up to the pipe. But loose throttle or choke shaft on there shouldn’t be an increase in rpm with ether applied