Spits, Sputters, Dies Under Load

Farmall Cub Forum -- Questions and answers to all of your Cub related issues.

Moderator: Team Cub

Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
User avatar
Glen
5+ Years
5+ Years
Posts: 2770
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: Spits, Sputters, Dies Under Load

Postby Glen » Tue Sep 04, 2018 8:18 pm

Hi,
Below is a page from the Cub owner's manual, showing how to adjust the valves, like was said before.

http://farmallcub.com/rudi_cub/www.clea ... e%2055.jpg

The valve cover is sometimes hard to get off the engine, with the parts that are around it.

User avatar
AgTires4295
5+ Years
5+ Years
Posts: 197
Joined: Fri Dec 30, 2011 7:36 pm
Zip Code: 20646
Tractors Owned: 1940 Farmall A
1947 Farmall H
1951 Farmall Cub
1970 Cub Cadet 127
1970 Simplicity Broadmoor 728 (x2)
1984 Cub Cadet 782
1964 Simplicity Landlord
2014 Simplicity Broadmoor 23/50
Location: La Plata, MD

Re: Spits, Sputters, Dies Under Load

Postby AgTires4295 » Wed Sep 05, 2018 8:49 am

Thanks for all of the continuous info!

I deleted the fuel bowl screen to maximize fuel flow and it's suddenly even worse. As soon as I turn the PTO on and go full throttle to the tall grass, it immediately sputters out.

I don't get it. It's turned into a fuel-flow/timing/governor issue from electrical I guess.

I've altered the timing by ear (so it may not be perfect) constantly and it's the same thing. I feel like if it was governor-related, it would not have gotten worse when I varied the fuel flow (removed fuel bowl screen).

Now it appears the fuel needle/seat/float may be stuck since I park it and the carb dribbles gas.

I've been frustrated before but this is starting to get annoying. I love working on this thing ...to an extent. Between shift work, an upset wife and whiney kids, I'm about to park it until next year. I can't stand to look at it right now.
Image
1940 Farmall A
1947 Farmall H
1951 Farmall Cub

User avatar
punchofdeath
Cub Star
Cub Star
Posts: 109
Joined: Sun May 28, 2017 3:42 pm
Zip Code: 25617
Tractors Owned: 1956 Cub
Circle of Safety: Y
Location: Southern West Virginia

Re: Spits, Sputters, Dies Under Load

Postby punchofdeath » Wed Sep 05, 2018 6:36 pm

AgTires4295 wrote:I'll have to see how to adjust the valves (uncharted territory there) but I'm sure every little bit of fine-tuning helps with this little machine. As far as I know it's NEVER been done.

Great pointers


I never had done valves on anything before and I went and get a tappet feeler gauge from advanced auto for $6 I think and once you figure out how to hold the wrenches its pretty simple. I didn't do the top dead center thing I just observed when the valves opened and closed when turning the engine by the hand crank. Once I figured out what they looked like when they were fully opened and closed I went ahead and adjusted what I could then turned the engine some more until the other valves closed. Might not be the proper by the book method but it worked just fine for me. I've got pictures of my valve clearances before and after. The Cub manual tells you what you need to know as far as the clearances are for the valves. if I remember rightly when I set mine the book called for .013 with the engine cold.

Not sure if your valves are the problem but perhaps you could consider them as something to do one evening.

~CG
High School Student | Class of 2018
Circle of Safety

Waif
501 Club
501 Club
Posts: 522
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Spits, Sputters, Dies Under Load

Postby Waif » Thu Sep 06, 2018 9:20 pm

AgTires4295 wrote:Thanks for all of the continuous info!

I deleted the fuel bowl screen to maximize fuel flow and it's suddenly even worse. As soon as I turn the PTO on and go full throttle to the tall grass, it immediately sputters out.

I don't get it. It's turned into a fuel-flow/timing/governor issue from electrical I guess.

I've altered the timing by ear (so it may not be perfect) constantly and it's the same thing. I feel like if it was governor-related, it would not have gotten worse when I varied the fuel flow (removed fuel bowl screen).

Now it appears the fuel needle/seat/float may be stuck since I park it and the carb dribbles gas.

I've been frustrated before but this is starting to get annoying. I love working on this thing ...to an extent. Between shift work, an upset wife and whiney kids, I'm about to park it until next year. I can't stand to look at it right now.


Don't shoot it while I check your zip code....O.K., not funny.

Had one Cub run ,then sputter out under load after warmed up good. Fuel starvation came to mind ...but my nose said it was dying rich. Quite a contrast that had me scratching my head.
Restarted just fine. Run without load fine. Grab a bucket load of leaves and it would stutter- sputter and conk out shortly after moving a ways.
Playing with the choke did not help.

The other tractor when the coil was bad would just plain stop running. No warning. Same effect as killing it with the switch.

Pulled plugs in sputterbutt and one plug gap was closed tight. Couldn't get my thinnest gauge in it...
As with most plug issues I put new plugs in after gapping them to spec. ,and kept the old ones. (They don't take up much room.)

Shutting gas off on both tractors when parking them after use keeps fuel starvation behavior/sound and method of conking out in mind.
Each tractor is different though. The older one has a slight surge before dying. The other just quiets and slows a little before stopping.

mozer71
Cub Star!!
Cub Star!!
Posts: 274
Joined: Wed Apr 04, 2018 1:33 pm
Zip Code: 22650

Re: Spits, Sputters, Dies Under Load

Postby mozer71 » Fri Sep 07, 2018 3:14 pm

.02 here. The carburator is picky about vacuum on each side of the throttle valve. The throttle shaft and bushings become worn over time but we don't know it because they have a layer of engine oil and grass packed around. Cleaning carb exposes this wear and here is a problem. The air plenum is supposed to be in time with the vacuum which pulls the fuel through the jets. Worn throttle shaft and bushings are like a short circuit. It is like a hole in your intake manifold.
Sure I was puzzled and in desperation to put some grease and 0-rings around shaft. It helped, so I made a more permanent repair.
Don't forget to replace that fine screen over your bowl. That is the protection of so many particles which can really screw the carb.

User avatar
AgTires4295
5+ Years
5+ Years
Posts: 197
Joined: Fri Dec 30, 2011 7:36 pm
Zip Code: 20646
Tractors Owned: 1940 Farmall A
1947 Farmall H
1951 Farmall Cub
1970 Cub Cadet 127
1970 Simplicity Broadmoor 728 (x2)
1984 Cub Cadet 782
1964 Simplicity Landlord
2014 Simplicity Broadmoor 23/50
Location: La Plata, MD

Re: Spits, Sputters, Dies Under Load

Postby AgTires4295 » Fri Sep 14, 2018 12:40 pm

Update: Spent the morning cleaning the block of dirt and grease. Adjusted the valves to spec (they were somewhat off) and that was much easier than I was expecting. Buttoned it back up and did a dry compression test.

Checked the spark plugs (all working). Sanded their contacts while at it.

Compression test:

Cylinder
1 -96 psi
2 -95 psi
3 -112 psi
4 -115 psi

I took apart, lubricated, and checked the governor arm for anything negative or restrictive. None. Spring looks good and functions as it should.

Put it all back together and fired it up (it immediately roared to life).

Drove it out of the barn and the same thing happened as usual within 1 minute of wide open throttle ...Spit, sputter, dead.

I'll be looking for that vacuum leak at the carb whenever I can get back at it.
Image
1940 Farmall A
1947 Farmall H
1951 Farmall Cub

butchs38
Cub Star
Cub Star
Posts: 51
Joined: Tue Mar 13, 2018 6:10 am
Zip Code: 07847
Tractors Owned: 1950 Cub
54 Blade

Re: Spits, Sputters, Dies Under Load

Postby butchs38 » Fri Sep 14, 2018 2:54 pm

If removing the fuel bowl screen made it worse there is also a screen in the tank I would check that also. It slides on top of sediment bowl inlet.
Attachments
ABC1315.jpeg

staninlowerAL
5+ Years
5+ Years
Posts: 3566
Joined: Fri Oct 29, 2010 11:34 pm
Zip Code: 36558
Tractors Owned: Cubs: (3)'49's, (1)'52, (1)'57 IH Cub LoBoy w/FH, (1)'72 154 Number Series Loboy, '76 Longstripe w/FH, Mowers: C-22, Bush Hog 412, Pennington 59, Woods RM42CF, Woods 42, assorted FCub plows, planters, discs, etc. OTHERS: '49 AC B & Ind. Sickle mower, '61 AC D12 Ser 2, '52 8N, '56 Ferguson 35 Deluxe, '53 MM BG (offset), (2) '49 Avery V's, '51 JD M (regular), '56 JD 420C, with Blade and fire plow, '85 JD 850 (Yanmar) w/72" belly mower, '76 Yanmar 1500, Sears Surburban's, MTD's, Jeeps & other misc. "treasures"
Circle of Safety: Y
Location: AL (Southwest)

Re: Spits, Sputters, Dies Under Load

Postby staninlowerAL » Fri Sep 14, 2018 3:03 pm

butchs38 wrote:If removing the fuel bowl screen made it worse there is also a screen in the tank I would check that also. It slides on top of sediment bowl inlet.

Must have been added somewhere in its previous life. Never seen one like that on OEM equipment.

butchs38
Cub Star
Cub Star
Posts: 51
Joined: Tue Mar 13, 2018 6:10 am
Zip Code: 07847
Tractors Owned: 1950 Cub
54 Blade

Re: Spits, Sputters, Dies Under Load

Postby butchs38 » Fri Sep 14, 2018 3:20 pm

Thats possible my 50 has one it also has a screen on inlet of carb inside where fuel line screws on.

User avatar
AgTires4295
5+ Years
5+ Years
Posts: 197
Joined: Fri Dec 30, 2011 7:36 pm
Zip Code: 20646
Tractors Owned: 1940 Farmall A
1947 Farmall H
1951 Farmall Cub
1970 Cub Cadet 127
1970 Simplicity Broadmoor 728 (x2)
1984 Cub Cadet 782
1964 Simplicity Landlord
2014 Simplicity Broadmoor 23/50
Location: La Plata, MD

Re: Spits, Sputters, Dies Under Load

Postby AgTires4295 » Fri Sep 14, 2018 3:44 pm

Yeah mine had that on it when I first brought the Cub back from the grave a few years back. Deleted it.

Just took off the carb, cleaned it entirely again for good measure and looked for any possibility of a vacuum leak anywhere. I paid close attention to the throttle attachment and noticed some play so I took out the butterfly valve, slid the assembly out and fit two plastic washers to tighten it up (thinking air has to be sneaking in through the slop).

Put it all back together and no luck. Same thing. I'm dead in the water and have no idea what to do unless I just dump dumb money at it and replace the carb, delete the fuel bowl, and whatever else comes to mind.

Any other ideas? I can't find a vacuum leak anywhere...
Image
1940 Farmall A
1947 Farmall H
1951 Farmall Cub

butchs38
Cub Star
Cub Star
Posts: 51
Joined: Tue Mar 13, 2018 6:10 am
Zip Code: 07847
Tractors Owned: 1950 Cub
54 Blade

Re: Spits, Sputters, Dies Under Load

Postby butchs38 » Fri Sep 14, 2018 5:45 pm

When it dies quickly take a look at the sentiment bowl and see how much gas is in it if its full I would look for a restriction in the fuel line a kink or dirt restricting flow. If the bowl is empty drain tank and take the strainer assembly off and check all ports for any restrictions also check shut off valve make sure its opening all the way. If the fuel line was replaced with a rubber one it could be soft inside and collapsing the ethanol in the gas will soften rubber thats not compatible with it.
Last edited by butchs38 on Sat Sep 15, 2018 5:57 pm, edited 1 time in total.

User avatar
Glen
5+ Years
5+ Years
Posts: 2770
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: Spits, Sputters, Dies Under Load

Postby Glen » Fri Sep 14, 2018 8:00 pm

Hi,
Too bad it is not working better.

Did you try a fuel flow test, remove the plug from the bottom of the carburetor, on an IH carb, and catch the gas in a clean can, then you can put it back in the gas tank later.
Let it run out for about 1 minute, it should flow steadily, and not stop.
At first lots will come out, that is gas that is in the carb. :)

If it does not flow well, there is a small screen in the carb inlet, that could need cleaning.
Below is a pic of it, from TM Tractor.

I have read on here of rust or dirt plugging inside a gas strainer, above the glass bowl. The man had to remove the strainer from the tank and remove the valve, and clean inside the casting.
Attachments
Cub carb 7.jpg
Cub carb 7.jpg (12.83 KiB) Viewed 155 times

k hutchins
5+ Years
5+ Years
Posts: 292
Joined: Tue Mar 27, 2012 5:48 pm
Zip Code: 48843
Tractors Owned: 1948 Farmall Cub
193 plow
1948 snow/grading blade
Woods 59 C3
Cub 144 cultivator
Cub 22 mower
Cub 172 one row planter
Original manuals for all the above

Re: Spits, Sputters, Dies Under Load

Postby k hutchins » Sat Sep 15, 2018 5:25 am

I had a problem with a restriction in the shut off valve/bowl area. When l removed the bowl and emptied/cleaned itthen turned my gas back on it only dripped into the bowl instead of flowing in. I was able to clear it by running a fine stiff wire down through the tank, then up through the bottom after removing the bowl. Then turning the gas on and off a couple times, seemed to flush out whatever was blocking it. With a clear inlet the bowl should fill fairly quickly. When you're sure you've got good flow there, then check your line, then check the carb. Follow the flow step by step, that way you can eliminate the problem.
Why is there never enough time to do the job right, but always enough time to do it over. :?:

staninlowerAL
5+ Years
5+ Years
Posts: 3566
Joined: Fri Oct 29, 2010 11:34 pm
Zip Code: 36558
Tractors Owned: Cubs: (3)'49's, (1)'52, (1)'57 IH Cub LoBoy w/FH, (1)'72 154 Number Series Loboy, '76 Longstripe w/FH, Mowers: C-22, Bush Hog 412, Pennington 59, Woods RM42CF, Woods 42, assorted FCub plows, planters, discs, etc. OTHERS: '49 AC B & Ind. Sickle mower, '61 AC D12 Ser 2, '52 8N, '56 Ferguson 35 Deluxe, '53 MM BG (offset), (2) '49 Avery V's, '51 JD M (regular), '56 JD 420C, with Blade and fire plow, '85 JD 850 (Yanmar) w/72" belly mower, '76 Yanmar 1500, Sears Surburban's, MTD's, Jeeps & other misc. "treasures"
Circle of Safety: Y
Location: AL (Southwest)

Re: Spits, Sputters, Dies Under Load

Postby staninlowerAL » Sat Sep 15, 2018 7:11 am

The cleaning process that k hutchins describes is made more difficult because the fuel shutoff valve does not have a straight passage top to bottom. There's two right angle bends in the flow path. The valve handle can be removed to allow access to the horizontal portion of the passage.

Waif
501 Club
501 Club
Posts: 522
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Spits, Sputters, Dies Under Load

Postby Waif » Sat Sep 15, 2018 10:56 am

Fuel flow test sounds great. Only costs labor too....

Next time it dies ,check heat temp .
Don't get burned!
I favor the distributor area. It receives fan air enough to be constant/ consistently reflecting operating temp ,in my opinion anyways..
A large older electric motor runs around 111 degree's roughly. You can touch it ,but you don't want to lean on it. On my 48 that is about where the magneto temp runs when tractor is being worked good.
When it has died from various maladies it often has followed running hot. As in yikes ,don't touch the magneto for more than a second.
Not a cooling issue as much as it has been multiple other issues ,but if temperature swelling causes resistance somewhere ,heat increases it...


  • Similar Topics
    Replies
    Views
    Last post

Return to “Farmall Cub”

Who is online

Users browsing this forum: jsfarmall, wrz and 2 guests