Farmall Cub Forum -- Questions and answers to all of your Cub related issues.
Sat Oct 06, 2012 7:07 pm
I drove my Cub for the first time this afternoon and experienced uneven engine speed. It seemed that the governor was "searching" for a proper speed. I had no problem keeping the engine running, but it continually surged back and forth, making for an uneven ride. Any diagnostic suggestions would be appreciated. Thanks, Stan.
By the way, as you may notice, I just posted another question (oil cup) right before this one. What is the better way to present questions when they are on unrelated subjects? Should I ask both questions in the same posting, or do most folks make two separate posts?
Sat Oct 06, 2012 7:24 pm
Usually it's a fuel problem when they start doing that. Check the fuel flow, sounds like somethings wrong in that area..
Sat Oct 06, 2012 7:28 pm
Check the throttle rod (from the governor rockshaft to the carb throttle shaft) and make sure it is not touching the engine block anywhere,. That can cause it to surge....
Sat Oct 06, 2012 7:30 pm
Have you made any recent changes to the carburetor or it's linkages?
Sun Oct 07, 2012 3:29 am
What is the better way to present questions when they are on unrelated subjects? Should I ask both questions in the same posting, or do most folks make two separate posts?
In response to your question about tech questions, the way you posted your questions gives readers an opportunity to see both questions at a glance while browsing the forum instead of just one.
Myself having expertise in some subjects and none in others may overlook your second question which I could possibly be of assistance with, but never would have read your second question having no expertise in the original question you asked in the subject line of a single forum posting.
In response to the governor question, sometimes the solution to the problem is a simple lubrication issue which is a cheap fix. If you haven't already, suspect any linkage pivot point between the governor and the carb, soaking them with your penatrant of choice to insure they operate freely before diving into the carb or governor system.
Sun Oct 07, 2012 7:42 am
Thanks for the responses. Although it is possible that there is a fuel flow issue, I tend to doubt it. The fuel tank was perfectly clean and free of rust, I have just installed a new fuel strainer assembly along with a new (steel) fuel line. There are no kinks in the line. The carb was disassembled, soaked in carb cleaner and reassembled with a new carb kit, after blowing out all the orfices. During my overhaul, I have had all the various linkages removed from the tractor, but I tried to be careful to avoid making any changes in the linkage adjustments. When I first started work on the Cub, I found the shaft coming out of the governor to be nearly frozen. I applied PB Blaster over a few days and freed that up, but I have not actually checked to see how free it is now. I will double check to see that it has not become stiff once again. If any of you have additional thoughts about what I might check, please feel free to share with me. Thanks much.
Sun Oct 07, 2012 7:59 am
Whenever the carb is removed, you should synchronize the governor with the carb. The step-by-step procedure is set forth beginning at the bottom of page 28 in the Blue Ribbon Service Manual GSS-1132.
Sun Oct 07, 2012 8:33 am
challenger wrote:Whenever the carb is removed, you should synchronize the governor with the carb. The step-by-step procedure is set forth beginning at the bottom of page 28 in the Blue Ribbon Service Manual GSS-1132.
Thats exactly.right. If you remove the carb for ANY reason, then you still have to readjust or check the linkages for adjustment when the carb is reinstalled. Also, as in my previous post, if the linkage even lightly brushes the engine block, it will cause the governor to lag and surge. I have seen people spend hours working on this and that only to find that was the problem (an easy fix)
Sun Oct 07, 2012 3:05 pm
I had the same problem with mine at first. Then I lubed all the linkage points from the carb, back to the governor. Problem solved.
Mon Oct 08, 2012 9:01 am
I sure did not know about the need for linkage adjustment upon removal of the carb and/or the manifold. I have read and printed out the referenced instructions and will give them a try in the next day or two. Thanks for all the informed assistance, folks. I will be reporting back.
Tue Oct 09, 2012 8:09 pm
FOLLOW-UP I had some time with the Cub this morning. I read the above referenced governor adjustment information (thanks, Challenger) and verified that the linkage moved freely and was without any interference. I pushed the tractor outside prior to cranking. (Easy enough on level concrete pavement.) I decided to try using the hand crank for a change, as I had never started it this way before. Well, what do you know - it started with a couple of pulls! At first, it idled very smoothly, without any fluctuation of the governor, but as it warmed up, it started to go up and down slightly. After warm-up I adjusted the idle screw by turning it in nearly one rotation. That seemed to smooth out the surging, so I hopped up and drove around a bit, but I am still getting the uneven throttle response while under the load of driving. I ran out of time, so I did not do the linkage adjustment today. I may get to that tomorrow. I really do not want to pull off the governor and go into it. Hopefully, linkage adjustment will resolve the issue.
Tue Oct 09, 2012 10:35 pm
The idle screw .. should be turned in until it seats, then back it out 1-1/2 turns. That should be about perfect.GSS-1132 - Fuel System
Then make sure that you lube the entire Governor Shaft Assembly
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