Carb carb question.

[First9n]

Last couple of times I used my 9N for mowing I noticed it was not Running quite up to snuff. Went to adjust the carb and noticed turning the air fuel screw made no change in the running. What's going on? Added note when I took the radiator out to replace the water pump I noticed that one of the plug wires had gotten into the belt and got cut in half. that explains the "not quite up to snuff" but would it have an effect on carb adjustments?

 

[HarryVanderpool]

On a scale of 1 to 10 how would you characterize yourself with the following description:
"I want to learn and master all design aspects of my very simple antique yet very useful tractor"?
We are all here for you and for many years but need a sense of commitment from you in terms of seriousness.
Your 9N is VERY easy to maintain but has to be maintained!

 

[Jim L WA]

Welcome to the forum First9n. To answer your question, no, the cut up plug wire would have no effect on the carburetor adjustment. Replace and properly rout the plug wire, put the carburetor adjustment approximately back to where it was and see how it runs.
In the future, once a carburetor has been adjusted, leave it alone. They don't go out of adjustment by themselves. Look for some other cause of not running right.

 

[old]

Last couple of times I used my 9N for mowing I noticed it was not Running quite up to snuff. Went to adjust the carb and noticed turning the air fuel screw made no change in the running. What's going on? Added note when I took the radiator out to replace the water pump I noticed that one of the plug wires had gotten into the belt and got cut in half. that explains the "not quite up to snuff" but would it have an effect on carb adjustments?

What happens when you add a bit if choke to it?? Can you turn the main jet adjustment to the point you can pul it out of the carb and it still run?? If you can you have a clogged carb

 

[Mad Farmer]

Carb full of crap gas/water?

Drain the bowl and see what comes out.

 

[fusion1]

If you were trying to adj Carb while engine is running on 3 cyl
you will not see any difference in the way it runs

 

[First9n]

On a scale of 1 to 10 how would you characterize yourself with the following description:
"I want to learn and master all design aspects of my very simple antique yet very useful tractor"?
We are all here for you and for many years but need a sense of commitment from you in terms of seriousness.
Your 9N is VERY easy to maintain but has to be maintained!

8.5

 

[First9n]

What happens when you add a bit if choke to it?? Can you turn the main jet adjustment to the point you can pul it out of the carb and it still run?? If you can you have a clogged c

I tore it apart before I read you post....would have been good to know.....sorry

 

[First9n]

Welcome to the forum First9n. To answer your question, no, the cut up plug wire would have no effect on the carburetor adjustment. Replace and properly rout the plug wire, put the carburetor adjustment approximately back to where it was and see how it runs.
In the future, once a carburetor has been adjusted, leave it alone. They don't go out of adjustment by themselves. Look for some other cause of not running right.

Good to know....what are your tips on how to adjust the carp correctly?

 

[Jim L WA]

Good to know....what are your tips on how to adjust the carp correctly?

Here is what my 9N service manual says. Start with the main jet, large screw on the top, 1 1/4 turns out from closed. A simple test for proper adjustment is to pull down the throttle suddenly when the tractor has a load. See if the engine speeds up at once without coughing or hesitating. If it does, open the main jet 1/8 turn at a time until the engine will speed up at once, evenly and steadily.
To adjust the idle jet, the smaller one on the side, with the engine warm, place the throttle all the way up then turn the idle jet down or in. Back it off approximately 2 1/2 turns, carefully noting the engine operation. Continue to back off adjusting screw until engine operates smoothly.
The above is for a 400 RPM idle speed. None of my tractors have never been set that low. So l don't pay much attention to idle mixture adjustment.

 

[First9n]

Here is what my 9N service manual says. Start with the main jet, large screw on the top, 1 1/4 turns out from closed. A simple test for proper adjustment is to pull down the throttle suddenly when the tractor has a load. See if the engine speeds up at once without coughing or hesitating. If it does, open the main jet 1/8 turn at a time until the engine will speed up at once, evenly and steadily.
To adjust the idle jet, the smaller one on the side, with the engine warm, place the throttle all the way up then turn the idle jet down or in. Back it off approximately 2 1/2 turns, carefully noting the engine operation. Continue to back off adjusting screw until engine operates smoothly.
The above is for a 400 RPM idle speed. None of my tractors have never been set that low. So l don't pay much attention to idle mixture adjustment.

Thank you for this information, which reminds me I do have a manual for this thing.....need to do some reading. I put a kit in the carb, soaked it overnight in cleaner, blew out all the holes and put in the kit, pre set the adjustment screws, and she fire right up. Screwing in the Idle jet has no effect on the running of the engine........What am I missing?

 

[R Geiger]

Last couple of times I used my 9N for mowing I noticed it was not Running quite up to snuff. Went to adjust the carb and noticed turning the air fuel screw made no change in the running. What's going on? Added note when I took the radiator out to replace the water pump I noticed that one of the plug wires had gotten into the belt and got cut in half. that explains the "not quite up to snuff" but would it have an effect on carb adjustments?

THe only time the idle screw adjustment works is when the rpm is very low.

 

[R Geiger]

Thank you for this information, which reminds me I do have a manual for this thing.....need to do some reading. I put a kit in the carb, soaked it overnight in cleaner, blew out all the holes and put in the kit, pre set the adjustment screws, and she fire right up. Screwing in the Idle jet has no effect on the running of the engine........What am I missing?

If you are sucking air in around the throttle valve shaft, you will be getting to much air and the air needle will do nothing. I don't worry about idle speed as I rarely run it at an idle low enough for the needle to work anyway.

 

[40sVintage]

Thank you for this information, which reminds me I do have a manual for this thing.....need to do some reading. I put a kit in the carb, soaked it overnight in cleaner, blew out all the holes and put in the kit, pre set the adjustment screws, and she fire right up. Screwing in the Idle jet has no effect on the running of the engine........What am I missing?

Check compression. As someone else said, if you're not running on all 4 it'll act like this.

Mine has the same problem, and I know the valves aren't closing all the way on #4 due to them being misadjusted.