Trouble with my 1949 Cub

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Glen
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Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
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Location: Wa.

Re: Trouble with my 1949 Cub

Postby Glen » Tue Feb 15, 2022 9:00 pm

WildFarmall wrote:I am pretty sure my oil pressure is too high as oil seeps out of the top of the oil container.

Hi,
Motor oil can seep from the oil filter cover when the oil pressure is the normal amount too, if the cover doesn't seal good enough.
The bolt is supposed to have a copper washer on it at the top, to seal the cover.
Below is a listing for it at TM Tractor.

http://www.tmtractor.com/new/en/287fp.htm

The cover can get rough where the washer goes on it from use over the years, turning the bolt can scar the cover, then the washer might not seal well.
You can remove the cover and check it, file the cover flat and smooth where the washer goes, if needed.

If it won't seal, I have needed to put a light coating of sealer on both sides of the washer to seal it.

It can leak at the big gasket too, like Don said above.
Below is TM Tractor's listing for a paper gasket, I think.
The paper gasket is what they sell with their Cub oil filters also. :)

http://www.tmtractor.com/new/en/136fp.htm

WildFarmall wrote: I assume that the spring is the regulator.

Yes, the oil pressure regulator spring has to be the right length, and have the right tension to let any excess oil pressure go out of the system.

The Cub and LoBoy service manual says that a Cub engine has a 35 lb oil pressure system, at full engine speed, which is 1800 RPM for a 1949 Cub.
They don't need a high pressure oil gauge.

Below are oil pressure gauges that TM Tractor has. It says on the page before, that they had them made in the USA to look like the originals.
The 1st one is like a 1949 Cub came with, as far as I know.

http://www.tmtractor.com/new/en/5732fp.htm

If you would rather have a gauge with numbers, they have this style also, with numbers. IH started using this style of gauge on Cubs in about 1956.

http://www.tmtractor.com/new/en/3291fp.htm

Below is info for doing a compression test, if you need it.

Remove all 4 spark plugs so they are out of the engine at the same time.
Use the starter for the test, not the hand crank.
Charge the battery fully before doing the test.
Charge a new battery too, they are not always fully charged. Use a small output battery charger, and let it charge slowly, it may take several hours.
Open the throttle fully, so the engine can get air for the test.
I write down the results so I have a record.

The Cub service manual says a Cub engine has 120 lbs of compression. That is probably for a new engine. Some less is ok, 90 lbs or more is ok. :)
Last edited by Glen on Wed Feb 16, 2022 8:31 pm, edited 1 time in total.

Eugene
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Re: Trouble with my 1949 Cub

Postby Eugene » Tue Feb 15, 2022 9:23 pm

WildFarmall wrote:I bought a new Oil Pressure Guage and will install and check that tomorrow.
You could have used the air compressor to test the gauge.

Functioning oil pressure regulator will limit the oil pressure to around 35 psi. Did the piston come out with the spring?
I understand that the compression should be 100 or better.
Ya. Better on a recently rebuilt engine. Hopefully around 120 psi.

Check the compression, then solve the ignition problem(s).
I have an excuse. CRS.

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Rick Spivey
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Re: Trouble with my 1949 Cub

Postby Rick Spivey » Wed Feb 16, 2022 7:34 am

Just a thought on your plug fouling. If it is caused by rich fuel mixture, it may be caused by the idle circuit and not the main jet. I have seen that on other cubs. The adjustment screw that is located on the top of the carburetor, at an angle, is the air mixture adjustment for the idle circuit. It controls the air flow, not the fuel, so turning it in would richen the mixture, while turning it out would lean it out. Adjust it to where you have a smooth idle with no black smoke, and to where you can accelerate quickly with no stumble. Good Luck at solving the issues!
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)

WildFarmall
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Tractors Owned: Uncle Hubert - 1940 Farmall A
Aunt Elsie - 1949 Farmall Cub

Re: Trouble with my 1949 Cub

Postby WildFarmall » Mon Feb 28, 2022 11:05 am

Thank you everyone! Here is my update: (note - I may be repeating some)
1. Bought a new carburetor from TM Tractor and installed
2. Repaired the hydraulic pump with a new seal kit.
3. Took out Oil Pressure relief valve and inspected. Looks good.
4. Put in new oil guage from TM Tractor. The old guage was defective as oil had seeped into the guage. The new guage works good and oil pressure is showing about 3/4 to the right.
5. Changed oil and checked level and it is remaining constant about 1/2 way on the dipstick.
6. Put a new copper washer on the oil filter shaft and there are now no leaks!
7. Replaced the gas line with a new 5/16 line that I made myself. Looks good and no leaks!
8. Started the engine and at first it ran rough but after about 15 minutes it started running smooth. Adjusted the idle screw behind carb to ;lower the rpm. Engine runs good after I used it a bit. There is no smoke now!
As to the compression on the cylinders is there any chance that the compression would get better with use? Someone I talked with suggested that with hard use the rings would "set" better and that the compression would improve a little> Any thoughts on this?
Again, I want to thank all of you for helping me out.

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Glen
10+ Years
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Posts: 6074
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: Trouble with my 1949 Cub

Postby Glen » Mon Feb 28, 2022 7:35 pm

Hi,
Good that you repaired those things, and the Cub is working better.

Yes, a rebuilt, or rebored engine usually needs to run and break in for a while, to improve the compression.
I would not run it hard at first, light loads for the first few hours of use.

Below is a page from the 1965 Cub and LoBoy operator's manual telling about engine break in, when the tractors were new.
I would think the engine speeds it says in the table are maximum speeds, not run it at that speed all the time, but I didn't make the table. :)

http://farmallcub.com/rudi_cub/www.clea ... age-07.jpg


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