C-140 carb question

[FAST 87]

This rod my finger is pointing at wiggles pretty good side to side. Is that normal on these wheel horse? If it’s not normal what do I need to do to fix this? It sounds like a lifter tapping at low idle.

[ZXT 2,401]

It's normal for it to do that, but it shouldn't. 40+ years of metal-on-metal wore the bore out some. I know Kohler sells little bushings that you put in to take up the slack, but I don't know the part number. Someone on here does though because that's where I learned of it. 

[Ed Kennell 38,021]

Side to side movement of the throttle plate shaft indicates wear in the bore.   This can be repaired by installing a bushing to tighten the clearance.

If the clearance becomes too great, excess air will be sucked into the carb upsetting the fuel/air  mixture.   This usually results in the necessity to close the choke to keep the engine running.

[FAST 87]

Just now, Ed Kennell said:

Side to side movement of the throttle plate shaft indicates wear in the bore.   This can be repaired by installing a bushing to tighten the clearance.

If the clearance becomes too great, excess air will be sucked into the carb upsetting the fuel/air  mixture.   This usually results in the necessity to close the choke to keep the engine running.

That’s where I’m at with this one. I have to crack the choke every now and then at mid throttle or it acts like it’s gonna stall.

[Ed Kennell 38,021]

Installing a bushing requires the removal of the carb to access the screws that bolt the throttle plate to the shaft.

If you choose to do this, we can supply some cautions and advice.

[ZXT 2,401]

Just now, Ed Kennell said:

Installing a bushing requires the removal of the carb to access the screws that bolt the throttle plate to the shaft.

If you choose to do this, we can supply some cautions and advice.

Ed, do you happen to know where everyone gets the kit to do this? My C120 could stand to have bushings put in.

[Ed Kennell 38,021]

It's been quite a while since I replaced any Jonah.   So I don't remember bore and OD sizes, but I remember buying brass bushings at ACE Hardware to do the job.

The caution is in removing the throttle plate screws.  They are normally peened over during installation to prevent loosening from vibration.  Before attempting to loosen the screws, it is necessary to grind away the peened area of the screw on the back side of the throttle plate shaft.    If you do not do this, the screws will probably break off.

[ZXT 2,401]

7 minutes ago, Ed Kennell said:

 

The caution is in removing the throttle plate screws.  They are normally peened over during installation to prevent loosening from vibration.  

I learned that more than once on Carter AFB and AVS carbs! Dang near impossible to get on the other side of the screw to grind it off where they'll come out correctly.

 

I'll do a little research and see if I can come up with specific specs on the bushings.

[FAST 87]

Thanks for the help with this guys. Definitely want my Horse working its best and not doing damage that can be helped. I had the carb off right after I bought it the other day and didn’t notice this moving then, I wished I had because I would have investigated it while I had it off. 

[81blackhood 168]

I just rebuilt my Kohler carburetor.  My throttle shaft was very lose with .0025 play in the shaft

 

 

I read that the following bronze thrust washers work well as bushing.  I installed two and no more slop.  

Edited October 7, 2019 by 81blackhood

[FAST 87]

Thank you very much.

4 minutes ago, 81blackhood said:

I just rebuilt my Kohler carburetor.  My throttle shaft was very lose with .0025 play in the shaft

 

 

I read that the following bronze thrust washers work well as bushing.  I installed two and no more slop.  

Thank you very much

[81blackhood 168]

@FAST got the washers of Amazon for like $11.  Made by Hillman. 👍

[FAST 87]

1 minute ago, 81blackhood said:

@FAST got the washers of Amazon for like $11.  Made by Hillman. 👍

Thank you I was just looking at them on Amazon and thinking if I should ask if they where the right ones. Thanks again.

[FAST 87]

Ordered them and they are on the way. Was it hard to do?

[81blackhood 168]

38 minutes ago, FAST said:

Ordered them and they are on the way. Was it hard to do?

Nope.  Once you get the shaft out install two washers.  They’ll be a snug fit.  Just lightly tap them into the bore.  

[oliver2-44 9,678]

After installing the bushings test the throttle shaft fit. If it’s snug take a 1/4 “ drill bit and gently ream the bushings by hand. 

[81blackhood 168]

6 minutes ago, oliver2-44 said:

After installing the bushings test the throttle shaft fit. If it’s snug take a 1/4 “ drill bit and gently ream the bushings by hand. 

Yep this but should not be necessary.  The inside of the washers are a good fit with very little play.  The outside is a press fit.   Just lightly tap them to get them in.   👍

[FAST 87]

2 minutes ago, 81blackhood said:

Yep this but should not be necessary.  The inside of the washers are a good fit with very little play.  The outside is a press fit.   Just lightly tap them to get them in.   👍

Are you having to take out old bushings that are worn then putting in the new ones?

[81blackhood 168]

The Kohler - Carter carbs have a counter bore in the top of the carb.  There’s no bushing to remove.  It’s empty space not being used if that makes sense.  Once you take the shaft out you’ll see.   With the washers installed the shaft is rotating at the top now and has no wear.   This is a cheap fix because the shaft doesn’t need replaced unless it’s severely worn.    

 

[Ed Kennell 38,021]

Please review post #7 before attempting to remove the throttle plate screws.

And remove any burrs on the shaft before reinstalling it in the new bushing.

Close the throttle to center the plate when you tighten the screws.

Use Loctite to secure the screws.

[roadapples 6,983]

Those screws file off by hand very easily. And the bushings are about a buck a piece at Ace hardware...