C-120 Auto #2

[Mr Magoo 226]

I started messing around with the 2nd C-120 Auto I have. I am not really sure what my future plans are for it. For now I just want to get it back up and running. It has been sitting for more than 12 years not running. Just for the heck of it, I put a battery in it after I knew the motor was free and it popped right off with a shot of gas to the carb. I had to laugh at that one. The other C-120 fought me hard to get it to start. One thing I found is that all of the safety switches on this one are bypassed. 

 

I know it has a blown head gasket, so that will probably be first on the list. All of the fuel lines are rotten and need replaced too. 

 

One other thing I found was that even with the manual bypass "Push Valve" turned to the open position, the transmission will not free wheel. Does anyone have any experience with what would cause that? The push valve screw on my other C-120 is stuck and I can't even turn it to try and open it. 

[Mr Magoo 226]

This would be #2.

[Mr Magoo 226]

You can see in the motor shot what I think indicates that the head gasket is leaking. Another thing about this one that is different from my other one is that the muffler is smaller in diameter. I'm not sure if that would hurt the motor or not. 

 

[Stormin 9,976]

  Cleaned up and that would be a nice looking machine. Does look like the head gasket is leaking. That's an easy fix. You could do a decoke and valve grind while the heads off. Muffler looks like a standard type to me and shouldn't be a problem.

  Can't help with the hydro valves, only to say if they can be removed, dismantled and freed off somehow.

Edited February 2, 2020 by Stormin

[ebinmaine 63,448]

Another nice looking machine there!

 

If you haven't already done so, check out this thread:

 

 

 

 

Alot of VERY helpful info.

 

I agree with @Stormin. Muffler is fine. Looks like the stick original.

 

It'd be a good idea to "mill" the head on sandpaper and a flat surface while it's off.

 

Others will be around to help with the hydro questions.

 

[rjg854 10,790]

All in all looks to be a tractor that should clean up and look good.

[Stormin 9,976]

50 minutes ago, ebinmaine said:

It'd be a good idea to "mill" the head on sandpaper and a flat surface while it's off.

 

Yes! Can be a boring job to do, but worth it. Some sheets of wet and dry or the US version. Piece of plate glass. An old mirror is good. (Don't use a mirror from in the house. You could get in trouble.) And something like paraffin, turpentine etc.

[ebinmaine 63,448]

1 hour ago, Stormin said:

old mirror is good. (Don't use a mirror from in the house. You could get in trouble

I don't want to see what I look like anyways so a mirror being all scratches is a good mirror.

 

I used an old storm door bottom section.

Tempered glass and fits quite well on top of a card table.

Sandwiched a blanket between table and glass.

 

 

[ZXT 2,394]

That's a nice looking tractor! Looks like it would clean up well with a degrease and wash job. 

 

What style of muffler does your other one have? If it's the pepper shaker style, you'll like this muffler way better. Much quieter and better sounding. 

 

Looks like you could easily have that one running around with a few hours work! Head gasket is an easy job.

[Mr Magoo 226]

27 minutes ago, ZXT said:

That's a nice looking tractor! Looks like it would clean up well with a degrease and wash job. 

 

What style of muffler does your other one have? If it's the pepper shaker style, you'll like this muffler way better. Much quieter and better sounding. 

 

Looks like you could easily have that one running around with a few hours work! Head gasket is an easy job.

The other muffler looks like this one, but this one is about an inch smaller in diameter. 

[Mr Magoo 226]

The mower deck needs some work on this one. It will need some welding and reinforcing. The spindles look pretty rough too. It looks like the aluminum housing has actually been eaten away by corrosion. 

 

I am not in love with this seat either! It is pretty darn awkward getting into it. 

[lynnmor 6,850]

Any known flat surface can be used to resurface the head.  Glass is usually good, but some can be distorted.  I use the ground cast iron surface on my DoAll bandsaw, but I wouldn't use the surface of a consumer grade stamped or aluminum table. 

[Mr Magoo 226]

Does anyone happen to know the part # for the little clips that hold the fuel line to the shroud on the Kohler engines?

[ebinmaine 63,448]

Might want to take one with you to a good Auto parts store.

Match em up...

[ZXT 2,394]

So... uh.. does it run yet?

[Mr Magoo 226]

9 hours ago, ZXT said:

So... uh.. does it run yet?

Not yet. Really just getting started with it. I had probably and acre of briers to clear and put the other C-120 to work getting the grass cut down. The grass had not had any cutting except for bush hogging in 10 years. It did a great job.

 

I need to pick up a good torque wrench so I can do the head gasket on this one. I do have an old beam style that I guess may be good enough. The other big thing will be getting tires for it. I may have to wait a bit to do that. I've only been back to work for a couple of weeks after being off for the last 4 month from shoulder surgery. Still catching up on some bills right now. I will repaint the wheel in the mean time. 

 

Got it cleaned up a bit last Sunday. Blew out all of the mouse nesting and cleaned up the oil on the block. I don't foresee any big issues with getting this one going.  

 

[ebinmaine 63,448]

4 minutes ago, Mr Magoo said:

good torque wrench ..... an old beam style

You'll be fine with that.

Just be sure to torque in 3 or 4 stages and get it as even as you can.

 

 

Have you hand planed the head?

That'd help ...

[Mr Magoo 226]

8 hours ago, ebinmaine said:

You'll be fine with that.

Just be sure to torque in 3 or 4 stages and get it as even as you can.

 

 

Have you hand planed the head?

That'd help ...

 

8 hours ago, ebinmaine said:

You'll be fine with that.

Just be sure to torque in 3 or 4 stages and get it as even as you can.

 

 

Have you hand planed the head?

That'd help ...

Not yet. I have not taken the head off yet. 

[chip61 655]

That machine already looks better than most of mine do!! That should make a great worker.

[Mr Magoo 226]

I finally got a day off and some time to do a little exploratory surgery on #2. Pulled the head off today. Not really liking what I'm seeing. I already knew the gasket was leaking. I didn't expect to see the large amount of carbon buildup. It seems like an awful lot. 

 

The other thing I noticed is that the piston is not centered in the cylinder. That does not seem right to me either. It was hard to get a shot of this, but if you look at the last picture you can just see the ring showing at about 4:00 and the piston is tighter opposite that. 

 

 

[ebinmaine 63,448]

Looks like a teardown is in order there.

Need to mic that for sure.

[ohiofarmer 3,158]

https://www.harborfreight.com/6-piece-telescoping-gauge-set-5649.html

 

 get a gauge set like this one. Measure across the bore at the top in the same direction as the wrist pin and lock the gauge. Then check various places at differing depths down the piston bore. i would bet that the bore is really egg shaped 90 degrees from the wrist pin.  I have a c-141 engine so bad that you can watch the bore open up a sixteenth of an inch as the piston descends into the bore. It does run, but really smokes

[Mr Magoo 226]

7 hours ago, ohiofarmer said:

https://www.harborfreight.com/6-piece-telescoping-gauge-set-5649.html

 

 get a gauge set like this one. Measure across the bore at the top in the same direction as the wrist pin and lock the gauge. Then check various places at differing depths down the piston bore. i would bet that the bore is really egg shaped 90 degrees from the wrist pin.  I have a c-141 engine so bad that you can watch the bore open up a sixteenth of an inch as the piston descends into the bore. It does run, but really smokes

I rotated the engine and was surprised to see that the offset does not appear to change as the piston goes up and down. I also tried to move the piston to see how much play there was and could not really detect any wiggle. 

 

I have a list of tools I put together from watching Norman of iSaveTractors You Tube tutorial on rebuilding one of these. I looked at those HF gauges. Do you all think they are accurate enough? I am buying one of their Icon torque wrenches. 

[tom2p 2,393]

if I recall correctly - it is fairly typical for a cylinder to show wear in that manner and in that area 

 

more wear perpendicular to the wrist pin (in line with crank / rod travel) - and toward the top and more often near greatest amount of heat 

on a short stroke high revving two stroke engine (for example) - this would lead to quick death (if not already dead) - but not familiar with Kohler ... Kohler might run for 5-10 years in this condition ... ? .. 

 

it is possible additional measurements toward the middle and bottom can help to determine - if wear is appreciable in those areas that could lead to piston rocking ... and obviously that is not a good thing ... 

 

[richmondred01 2,209]

Before spending any money on a telescopic gauge you will also need a micrometer to accurately take the measurement after gaging.

If this is going to be the only engine you rebuild then take it to the machine shop where they have accurate tools not the stuff you buy at harbor freight where 99% of the products sold are from the country that brought us covid19, non functioning respirators and faulty testing equipment.

If you want to continue to rebuild engines or do precision measurements invest in a quality instrument. 
Don’t get me wrong, Harbor Freight has its place for one time use or disposable equipment but certainly not accurate or daily used tools. I know I’m going to take heat for this post and people are going to say I bought so and so from harbor freight and it’s lasted bla bla bla....

Here’s the tools I use for cylinders.

Machine shops have even better inside micrometers.

Edited April 12, 2020 by richmondred01