Throttle lag/ not sensitive

[punchofdeath]

Today while I was disking my neighbors garden my cub started kind of hunting. It didn’t do this until I was well into the job. What it done is it started dropping some rpms then it would pick back up then repeat the process it was like when someone is slowly dozing off then quickly raise back up when they realize it. When sitting still I throttled down then back up a notch and it just sat there for about five seconds then slowly picked back up. It still has power because I went ahead and finished the job. I’m personally thinking it might be something sticking in the governor but it only done this once it got hot. I’m not a master at working on a cub either though. It done this two days ago after I had worked it for a while but I just thought it was being ornery so I went ahead and parked it for the day. It also doesn’t like to be throttled up quick which I would expect because it doesn’t have one of those little pumps on the carb for when you throttle real quick.

I typed this on my phone so if it’s jumbled up or something doesn’t make sense let me know.

https://youtu.be/PoY1_HYHgFc
Video of me moving my throttle linkage while the governor is set at full throttle. I don’t know if it contributes anything to an answer but it might help. it’s a homemade part but it’s always worked fine. I don’t know the story on the original linkage

[tmays]

Most likely cause of ‘hunting’ is not enough fuel flow.

[JimCub48]

Can't tell for sure from your video but it looks like your missing the govenor spring.

[punchofdeath]

The spring is on the governor. The throttle works fine it's just when it gets hot it starts "dozing off" then it'll pick back up real quick. I'll try pulling the main jet on the carb tomorrow and see if something is lodged in it if I don't get any ideas between now and then.

[Dale Finch]

It's hard to tell, but I don't see any corresponding movement in the gov when you are moving the carb/gov connecting rod back and forth. MIGHT be that the keyway in the gov rockshaft extension (#30 below) is worn. Some folks have recommended putting some JB WELD on the keyway end where it enters the Gov spring throttle lever (#11):

[Waif]

If after inspecting your governors linkage and response , if you find nothing ....Fuel as also mentioned would be good to check .
Is your gas cap stock? Be sure vent is working ( with cold tank and fuel after tractor has sat a while). If a new style ( one can be had free if not) check it too.
If any rubber lines ,check them for being too soft and collapsing. If steel ,check for a spot where too much heat can be absorbed. Add a heat sink if line cannot be moved.

You mentioned checking for obstructions. Fuel restriction sounds like a good possibility. You'll know soon....

[punchofdeath]

I got looking into the set up and I think my problem is what's shown in this picture here. https://imgur.com/a/jtxhK
The spring holes for the governor spring look quite a bit bigger than the wire(?) the spring is made out of.

I checked parts 30 and 11 for play and it was pretty solid. Not bound up kind of solid but no play.
http://www.farmallcub.info/manuals/cub_parts_tc-37f_rev_3/Page%2012-18.jpg

Could this be my problem or should I check else where?
Also theres probably about five gallons of fuel so it has plenty of gravity in there. Breather shouldn't be clogged because it's usually wet around the gas cap..(stock cap, need to sign up for the new one) Fuel lines are rubber and there's a filter inline but it's got a good angle on it to not stop flowing. Haven't checked anything with fuel system as I haven't had the time to today. Just went and checked what I could real quick.

[Jim Becker]

. . . It done this two days ago after I had worked it . . .

Any chance you put a new fuel filter on?

[punchofdeath]

Any chance you put a new fuel filter on?

No, it has had the same filter on it for a while now. Never had any fuel problems before aside from when there isn't enough gas in the tank for the gravity feed. I can check the fuel flow below the filter tomorrow to see if that might be the problem. Did you see the picture I linked showing my governer spring throttle lever? the holes in it looked a little big but I don't know if that's normal or worn. If the picture isn't good enough I can try to get a better one

[Waif]

There is plenty more hole than spring on mine.
I have some slop in the linkage where #30 is keyed ,but not great lag in response. Or I'm just used to it! l.o.l..

[mva1958]

I had a similar problem with lagging/hunting/loss of power - a quick clean-out of the carb jet solved it. Run a very thin wire through the hole in the end of the jet.

[Glen]

Hi,
The holes in the governor linkage are bigger than the spring material.
Below is a pic from TM Tractor showing them.

Waif, there should be no play where shaft number 30 fits into the hole at number 8 in the parts pic. The wear is in a turning direction. It is common for them to wear there, and become loose.
It is not number 11, like was said above.

Wear there wastes the movement of the governor, the governor turns the shaft, but the carburetor valve does not move, because of the wear. So the governor has to move more, it causes slow response.
You can see the hole in number 8 in the pic below also.

[Waif]

Hi,
The holes in the governor linkage are bigger than the spring material.
Below is a pic from TM Tractor showing them.

Waif, there should be no play where shaft number 30 fits into the hole at number 8 in the parts pic. The wear is in a turning direction. It is common for them to wear there, and become loose.
It is not number 11, like was said above.

Wear there wastes the movement of the governor, the governor turns the shaft, but the carburetor valve does not move, because of the wear. So the governor has to move more, it causes slow response.
You can see the hole in number 8 in the pic below also.

Thanks Glen. That looks like the critter.
Sure is nice to approach a wear caused condition with the former knowledge and experience of others behind us/ me!