Governor failure?

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DavidG
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Tractors Owned: 1972 IH Cub
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Governor failure?

Postby DavidG » Tue Jun 20, 2017 7:43 am

So I got a great Cub from Boss Hog four years ago, hasn't broken down once until now. Spreading fertilizer yesterday, going along normally the engine dies. Bumpy ground, nothing excessive or violent, but the governor was working to keep up. Restart, ran weekly for a second, dies. Repeat, no change. Seems like a fuel issue, have flow through carb, clean carb and reinstall, starts right up -- I feel great but turns out that wasn't the issue! Looks like the real issue is the rocker arm connected to the rod to the carb throttle isn't working properly, and I probably moved it around when replacing the carb to a position that allowed the tractor to run.

I can adjust throttle from the quadrant, but not smoothly -- as if it only raises rpm when I've moved the lever far enough to pull on something directly, the governor doesn't "notice" and react to minor adjustments. Related, the arm attached to the carb does not return to return to idle (rotating towards the radiator) on its own. Critacally, under load the governor does not respond to increase throttle and maintain rpm. The governor DOES seem like it limits high rpm -- it pushes back in a seemingly-normal way if I push the carb throttle rod open with my finger. I am being careful/nervous about overspeeding, regardless.

Currently I have bypassed the governor with a rubberband (decrease throttle) and string to pull on (increase throttle), and can manually control the engine so it sounds like what I expect a working governor to do. I'm back in the field but obviously this is not a permanent fix. I don't read a lot about governors, and it seems like they don't fail too often. So my question is, is this almost certainly a governor problem? Do you recognize the ways a governor might fail and cause this issue? Or is it something else going on? The issue was sudden, as if something broke. The governor spring is still there the same as it ever was.

Thanks for any diagnostic help.
David
Vegetable farming with a Cub, http://www.secondspringcsa.com

Waif
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Re: Governor failure?

Postby Waif » Tue Jun 20, 2017 8:46 am

I'd study linkage ,and after it is confirmed to be working without binding or too much slop look at the governed linkage near/ at carb and be sure the threaded rod is adjusted properly.

Check for a egged out hole where linkage turns a rod through ears/ brackets to governor in front of engine. Be sure it moves freely.

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Rick Spivey
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Re: Governor failure?

Postby Rick Spivey » Tue Jun 20, 2017 5:18 pm

Sounds like the small woodruff key that keys the cross shaft to the governor gave up the ghost. They can get sloppy over years of use, yours may have just become very sloppy to the point of failure. Or the key somehow broke or came out. Look for slop in the cross shaft that crosses the front of the engine. Check it with the engine off for free play or slop. Search on here for ways to fix, or find replacement parts, if that is the problem.
Rick Spivey
'52 Cub ("Great Personality") 148xxx
'48 Cub with FH ("Gunny Cub") 38xxx
'57 Lambretta (a slow work in progress)
'74 Triumph TR6 (Mama's toy)

DavidG
5+ Years
5+ Years
Posts: 70
Joined: Sat Mar 06, 2010 6:55 am
Zip Code: 20132
Tractors Owned: 1972 IH Cub
1976 IH Cub
1979 IH 884
Circle of Safety: Y
Location: Northern Virginia

Re: Governor failure?

Postby DavidG » Wed Jun 21, 2017 12:41 pm

Rick, no kidding, that cross shaft is supposed to be tight with the tractor off? It has enough play to move the throttle butterfly basically from idle to full throttle. Humorously, I did suspect this and went to check a neighbors old Cub, which felt similar, so I was reassured. But it must have the same wear. I think I remember this fix and hassles involved from reading about it a while ago.

Is it likely that this is the only cause here, or would this be only one of a chain of repairs? I mean other than fixing wallowed out spring holes, replacing the spring, adjusting linkage, etc. Is it likely that nothing is wrong inside the governor, or is there a way to determine this? Like if after removing the cross shaft, operating the carb throttle manually and seeing if the shaft out of the governor is turning to attempt to counteract it?

Thanks for your help here,
David
Vegetable farming with a Cub, http://www.secondspringcsa.com

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Rick Spivey
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Posts: 2146
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Zip Code: 29518
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Re: Governor failure?

Postby Rick Spivey » Wed Jun 21, 2017 5:57 pm

I would suspect the more simple and common faults first, as you have mentioned. The governor internals rarely need attention, although not unheard of to have some wear. Find all the slop points and fix those, I suspect your throttle will respond as it should.
Rick Spivey
'52 Cub ("Great Personality") 148xxx
'48 Cub with FH ("Gunny Cub") 38xxx
'57 Lambretta (a slow work in progress)
'74 Triumph TR6 (Mama's toy)

DavidG
5+ Years
5+ Years
Posts: 70
Joined: Sat Mar 06, 2010 6:55 am
Zip Code: 20132
Tractors Owned: 1972 IH Cub
1976 IH Cub
1979 IH 884
Circle of Safety: Y
Location: Northern Virginia

Re: Governor failure?

Postby DavidG » Thu Jul 13, 2017 5:53 am

Well, I read all the past threads about the woodruff key repair, and took a closer look at things getting ready to do the repair. I can see the key, and it is firmly in there. The spring lever and rockshaft extension are solidly connected, and I can feel that the shaft out of the governor also turns when I rotate the carb side of the rockshaft by hand. I'm pretty sure I could feel the roll pin in the spring lever. As Rick asked, there IS play in the system with the tractor off -- I can turn the rockshaft extension but it's ALSO turning the spring lever and shaft into the governor! The spring holes are wallowed out enough to allow this play to occur.

With the tractor off, is it just the spring that prevents the shaft from being able to be turned, or is there something in the governor that prevents tits shaft from moving? IE, with no spring installed, should the rockshaft be able to move? I also found about 1/8 or 3/32 of in-out play in the shaft; I could pull out on the shaft and it'd move that much in+out of the governor.

Thanks for any further insight...
-David
Vegetable farming with a Cub, http://www.secondspringcsa.com


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