C120 throttle issue

[Mike_c120 33]

Looking for some help/pictures... I recently installed a new carburetor on my C120 with K301 on it... with that being said, I’m having an issue with installing the choke lever, but the biggest issue I’m having is when I put the throttle all the way up, the tractor revs to about 5000 rpm and sounds like small block Chevy wide open, but once I engage the pto with my 42inch deck on the tractor bogs down. Any help would really be appreciated, pictures also of the choke hooked up to the carburetor and even recommendations for different carburetors would be amazing!

 

thanks,

mike

[8ntruck 7,254]

Sounds like you have a governor issue.  Either the governor itself, or the linkage between the governor and carb.

 

My knowledge of governors is enough to make me dangerous.  I'm sure someone will be along soon with advice and pictures to help you.

[Mike_c120 33]

8ntruck, thank you for the fast response. I was thinking governor also.. more I look the linkage between the throttle lever and cable for the carb has definitely been messed with and slapped together with some make shift thinking

[Mike_c120 33]

6 minutes ago, 8ntruck said:

Sounds like you have a governor issue.  Either the governor itself, or the linkage between the governor and carb.

 

My knowledge of governors is enough to make me dangerous.  I'm sure someone will be along soon with advice and pictures to help you.

 
8ntruck, thank you for the fast response. I was thinking governor also.. more I look the linkage between the throttle lever and cable for the carb has definitely been messed with and slapped together with some make shift thinking

[WHGuy413 2,769]

6 minutes ago, 8ntruck said:

 

 

My knowledge of governors is enough to make me dangerous.  I'm sure someone will be along soon with advice and pictures to help you.

Haha you have that issue too? I always end up asking a friend.

[TJ5208 1,824]

Yeah I would say it's the governor.

[daveoman1966 3,768]

. This is my C-160.  The C-120 otter be the same... 

[Handy Don 13,053]

Some of the slickest engineering on these small engines went into calculating the components of the throttle input vs. governed output. 

What force does the governor exert on the arm at what RPM?

What spring will interact properly with that force (pull vs. displacement).

What levers, linkages, and cables will get to what rotation of the throttle plate do that well and reliably?

Whew!

[peter lena 8,968]

@daveoman1966 noticing an oil film on the related area , probably from aerosol lubricant attempt? that very high screaming speed , is scary enough . something I have been doing for years , is to regularly lubricate both ends of that , governor shaft area , till the rust starts to run out , just do it , worth a try . another NON RELATED  glairing issue , is the great pictures of the fuel pump to carb fuel hose connection , have something right there that helps quick starts , will not dare to mention it , hope you find your gov issue , pete

[squonk 41,895]

Make  sure your gov. lever STOPS when moving to the right. There has been a high amount of broken governor levers were the arm touches the gov. gear. If that has happened the engine needs to be completely torn down. No amount of fiddling will fix it.

[Mike_c120 33]

On 2/27/2022 at 9:20 PM, daveoman1966 said:

. This is my C-160.  The C-120 otter be the same... 

Daveoman1966,

thank you for the awesome pictures ! I can tell mine has definitely been slightly abused because some of my parts on the throttle assembly have a little more play than normal, now I have something to go off of. I appreciate it!

[Mike_c120 33]

4 hours ago, squonk said:

Make  sure your gov. lever STOPS when moving to the right. There has been a high amount of broken governor levers were the arm touches the gov. gear. If that has happened the engine needs to be completely torn down. No amount of fiddling will fix it.

Awesome thank you, yeah I’m going to be tinkering on it again today to try and get her running right again! Snow keeps coming and need the plow!! Lol

[squonk 41,895]

8 minutes ago, Mike_c120 said:

Awesome thank you, yeah I’m going to be tinkering on it again today to try and get her running right again! Snow keeps coming and need the plow!! Lol

The shaft being chinched down by the bolt clamp in this pic must stop while being rotated counter clockwise. Unhook the arm linkage and move the big lever to the right. It should stop after a little movement. If it doesn't don't waste your time adjusting anything.

 

 

You have one of these broken tabs.

 

Also: See the little l shaped bracket with the hole in it right above the fuel pump? This is the high speed stop. Make sure it's there.

 

 

Edited March 1, 2022 by squonk

[Mike_c120 33]

On 3/1/2022 at 12:38 PM, squonk said:

The shaft being chinched down by the bolt clamp in this pic must stop while being rotated counter clockwise. Unhook the arm linkage and move the big lever to the right. It should stop after a little movement. If it doesn't don't waste your time adjusting anything.

 

 

You have one of these broken tabs.

 

Also: See the little l shaped bracket with the hole in it right above the fuel pump? This is the high speed stop. Make sure it's there.

 

 

Okay I know I’m late to getting back, but I have finally had time to mess with it, I put a new carb on and I used vice grips to turn that shaft and yes it only turned a little counter clockwise. After that I cinched the bolt back down and still the tractor goes nuts when you put it to full throttle. What should be my next step with this? 

[kpinnc 13,080]

I suggest a light spring between the governor arm and throttle tab. It won't affect the governor action, but will keep slop out of the response. From there your adjustments will work much better.

 

The tab and governor arm both have a hole for the spring from the factory. You can find them at most any hardware store.

 

 

[squonk 41,895]

That little L shaped bracket above your fuel pump is your hi-speed stop. Looks like it needs adjustment.

[peter lena 8,968]

@kpinnc  like your light spring application on that throttle plate pull. been experimenting with those for a long time , found the very lightest touch to do the job, like this one , the top horizontal spring is perfect , have not been able to find the # specs on that , if I do will be sure to put it on this site , note perforated pull point , easily attached to a mount bolt , for choke / throttle cable spring pull . that pull to assist zero choke and zero throttle , along with SUPER LUBE , makes those cables work with total ease , worth a try , pete  

 

[kpinnc 13,080]

4 hours ago, peter lena said:

like your light spring application on that throttle plate pull. been experimenting with those for a long time , found the very lightest touch to do the job, like this one , the top horizontal spring is perfect , have not been able to find the # specs on that , if I do will be sure to put it on this site , note perforated pull point , easily attached to a mount bolt , for choke / throttle cable spring pull .

 

Pete,

 

I like yours as well, though they perform different functions. The spring I use only takes the slop out of the throttle linkage, where yours acts as an assist to the throttle cable.

 

Combining both might be worth checking out. I might try something like that.

[peter lena 8,968]

@kpinnc  yes found that that almost delicate touch  on that throttle front plate , was just right , pulling from the same spot, those just enough cable pull springs , enhance the closing , pushing action of the cable . did a number of spring mount points and springs , just looking for a smooth cable close assist . thats what  just started to work easier with every open and close , matter of fact going out now to try and find that lite spring ,type / number , so I can refer to it . realize a lot of my set ups is like gilding the Lilly . just what I like to do , pete