Cub lo-boy won't idle down.

[mdm1]

Cub lo-boy started and ran good. Mowed about an hour. At the start the engine would idle and throttle up. After mowing shut it off and started it and it shows no response to the throttle. Runs at the same speed it did when I was mowing. I had changed the carb so I thought maybe the rod to the carb had come off. No luck. When the engine is running I can't move the throttle rod at the carb. If I shut it off the rod and throttle plate move as they should. Only replaced carb didn't touch any of the linkage rods. When you move the rod you can feel spring tension on it. It doesn't just slop back and forth.

 

[old]

Cub lo-boy started and ran good. Mowed about an hour. At the start the engine would idle and throttle up. After mowing shut it off and started it and it shows no response to the throttle. Runs at the same speed it did when I was mowing. I had changed the carb so I thought maybe the rod to the carb had come off. No luck. When the engine is running I can't move the throttle rod at the carb. If I shut it off the rod and throttle plate move as they should. Only replaced carb didn't touch any of the linkage rods. When you move the rod you can feel spring tension on it. It doesn't just slop back and forth.

Spring broken in the gov will cause a problem like that

 

[mdm1]

Never had a gov apart. Guess will be checking things out.

 

[wore out]

Never had a gov apart. Guess will be checking things out.

Check to be sure the screws holding the butterfly to the carburetor's throttle shaft haven't come loose.

If you are feeling spring tension when you move the carb linkage with the engine stopped the governor spring hasn't broken.

Probably COULD be some other problem inside the governor, however, I can't think of WHAT would cause the "binding when running" issue.

Be aware that if you take the governor apart you can get the ignition system "out of time", or break things if the governor shaft slot and distributor or mag drive "tang" get out of engagement and you then tighten up the governor cover mounting bolts.

 

[mdm1]

I will check the carb first. That would be easier to start with. I guess I didn't explain to well. I can't move the shaft when it is running which would lead me to believe the governor is holding it like it should. Thanks for the idea.

 

[Jim Becker]

After you installed the carb, did you adjust the length of the control rod between the governor and carb? You need to adjust it by the book and make sure it moves freely without any binding. Not doing this can cause all sort of misbehavior.

There is rarely trouble inside the governor.

 

[mdm1]

I did not adjust the rod. The tractor ran fine after installing the new carb. It would idle and accelerate as it should. Even yesterday it was fine when I started to mow. Didn't really notice any change in the engine when I was mowing. Will be back by it on Wed.

 

[grandpa Love]

There isn't a spring in the governor (unless you count the little surge spring behind the big nut on the front) the governor spring is on the outside. Easy test, drive up hill does bog down?? Now drive down hill,does it rev way up??? Replace the spring. But that doesn't appear to be your main issue.

 

[grandpa Love]

There isn't a spring in the governor (unless you count the little surge spring behind the big nut on the front) the governor spring is on the outside. Easy test, drive up hill does bog down?? Now drive down hill,does it rev way up??? Replace the spring. But that doesn't appear to be your main issue.

After you installed the carb, did you adjust the length of the control rod between the governor and carb? You need to adjust it by the book and make sure it moves freely without any binding. Not doing this can cause all sort of misbehavior.

There is rarely trouble inside the governor.

This guy knows!!

 

[mdm1]

I was mowing up and down a hill. Didn't notice any change. In all honesty it seemed to happen when I parked it for a few minutes and then started up again. I have replaced that spring before. I live under Murphy's law I think.

 

[BarnyardEngineering]

I was mowing up and down a hill. Didn't notice any change. In all honesty it seemed to happen when I parked it for a few minutes and then started up again. I have replaced that spring before. I live under Murphy's law I think.

It's either that spring has broken, or the thrust bearing inside the governor has disintegrated. One of them causes the engine to just idle. The other causes the engine to run full throttle all the time. I can't remember which is which.

Obviously if the spring is intact then the thrust bearing has failed.

 

[mdm1]

When I previously replaced the spring it won't run full throttle with the broke spring.

 

[mdm1]

Got back to the tractor today. Checked carb disc screws they were fine. Made sure all the linkages were working and they were. Fired it up and it would idle down and throttle up as it should. No idea what I did. Maybe something was just hung up a little and moving rods etc by hand freed it. Or maybe the tractor fairy came by and fixed it! Thanks for all the thoughts and suggestions I will try to remember them in the future. Mike