New to me cub...no start

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cpy911
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New to me cub...no start

Postby cpy911 » Mon Jul 04, 2022 12:17 am

I recently inherited my late father-in-law's cub and we are working on getting it started.
First, we replaced the battery and got it to crank. Checked for spark, but no spark to the plugs. Took off the distributor cap and cleaned the center rotating contact (sorry, don't know the correct name for it). Checked again for spark and had spark at the plugs with the spark plug tester. Cranked over and was trying to start but no go. We then pulled the plugs and they were nasty in bad shape. So we replaced the plugs. In the meantime, the battery had drained. Got the battery charged fully and tried to start again with new plugs, but only got a engaging sound from the starter (no cranking). Tried this a couple times and got a little some smoke that came from starter switch area. I then stopped and came here. What should be my next step? I was thinking of trying to rotate the engine by hand (I don't have a crank tool) and try to loosen things up. Also, the oil in there is dirty and about 5 years old...should I change it before proceeding as well?

Thank you!

https://photos.app.goo.gl/6iQghDwZKvgNhEvv9
https://photos.app.goo.gl/6iQghDwZKvgNhEvv9
https://photos.app.goo.gl/5BRyrUVxnumy1QGw6

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Glen
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Re: New to me cub...no start

Postby Glen » Mon Jul 04, 2022 2:25 am

Hi,
The Cub looks good in the pictures.
Thanks for the pic of the serial number plate, the Cub is a 1948, as shown in the serial number list at the top of the page at Cub Info.

The rotating part under the magneto cap is the rotor.
A 1948 Cub came with a magneto. The Battery Ignition unit came out during 1950, and some Cubs were changed to it.
You need to identify which unit the Cub has so we can help work on it.
A 1948 Cub is originally 6 volts, with positive ground.
People change them sometimes to 12 volts negative ground, it needs a different generator or alternator to do that.
You didn't say which voltage it is.

It sounds like the starter switch on top of the starter is making poor contact inside.
I would remove it and sand the posts in it, and the post on top of the starter with fine sandpaper.
Disconnect the battery ground cable before disconnecting the cable at the starter switch.

It's possible the posts in the switch are burned so much it won't work right.
Sand the post on the starter as little as you can to clean it up, the post is not easy to replace, it is usually soldered inside the starter. Hopefully that post is still good, don't replace it unless it is bad.
Usually people send the starter to a starter repair shop to have that post replaced, and soldered inside the starter.
Wipe off all sanding with a clean rag.

The switch has to have 2 thin pieces of insulation inside the switch, at each side.
Be sure they are there, and put them in in the right positions when putting the switch on again.
The switch can short inside without them.

Below is a listing at TM Tractor for a new starter switch, you can look at the pics. :)

http://www.tmtractor.com/new/el/2543fp.htm

Eugene
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Re: New to me cub...no start

Postby Eugene » Mon Jul 04, 2022 8:18 am

Start with compression tests, dry then wet. If the tractor sat for a length of time, quite possible a valve or two is stuck open.

Type of ignition system? Magneto or battery powered.
I have an excuse. CRS.

cpy911
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Re: New to me cub...no start

Postby cpy911 » Mon Jul 04, 2022 11:35 am

Thank you for the comments. I have taken pictures of the alternator, coil (says 12V on it) and starter. The battery that was there and that we replaced was 12V. Everything is pointing to a 12V system upgrade at some point. So that is what we should work under. I will look into the starter switch and see if I can clean it up.

In order to check compression, I will need to buy a compression gauge and I assume it needs to at least crank? So, getting it to crank is the next step?
Attachments
IMG_6283.jpg
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IMG_6284.jpg

Bob McCarty
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Re: New to me cub...no start

Postby Bob McCarty » Mon Jul 04, 2022 12:02 pm

Some auto parts stores will loan test equipment. If you have a NAPA, Autozone, etc. nearby, you might call and ask. You can hand crank it to test for compression, but the results won't be as accurate.
"We don't need to think more,
we need to think differently."
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Don McCombs
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Re: New to me cub...no start

Postby Don McCombs » Mon Jul 04, 2022 12:48 pm

The electrical tape wrapped around the starter end of the battery to starter cable would lead one the suspect that you might have some corrosion under that tape, leading to poor current flow. Check and clean ALL connections in the starting circuit.
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Eugene
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Re: New to me cub...no start

Postby Eugene » Mon Jul 04, 2022 1:15 pm

Some auto parts stores loan test equipment. You could probably borrow one from a neighbor farmer or mechanic.

Fix the starter since you don't have a hand crank. Purchase a hand crank after you get the tractor running.

You need a 12 volt coil with internal resister or 12 voilt coil with a ballast resister. Check the printing on the side of the coil. I couldn't read the printing.
I have an excuse. CRS.

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Glen
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Re: New to me cub...no start

Postby Glen » Mon Jul 04, 2022 5:30 pm

Hi,
Thanks for posting the pictures.

The Cub still has the original style magneto. It has been changed to use an automotive style coil, using the battery power.
The magneto coil may have quit, and someone put on the other coil.
The magneto coil is under the cover on top of the magneto, where the post for the ignition wire is.
The magneto coil originally isn't connected to battery power.

While the hood is off, I would oil the fan hub.

Below is a page from the 1949 Cub owner's manual, telling how to oil the fan hub.
The original fan hubs use light motor oil for lube.
They can get low if nobody checks them, then the fan bearing can wear, or the fan can seize up.

http://farmallcub.com/rudi_cub/www.clea ... age-28.jpg

Hold the fan blades with the engine off, and wiggle them from side to side, and check for bearing wear in the fan hub. It should have no looseness sideways.

I use a pump oil can to put clean, light motor oil in the hub.
Be careful to not lose the small gasket that should be on the oil filler screw, it might be stuck on the hub.

You can give the hub a partial oil change by putting in the oil like the manual says, put in the filler screw, then turn the engine over 10 or 15 times, then drain the excess oil out, like the manual says.

The original hubs have no oil seal at the rear of them, oil may leak out if you turn over the engine before draining the excess out.
The hubs seem to hold oil usually, if it is at the right level.

The alternator belt is out at the end of it's adjustment. If it needs tightening in the future there is no way to tighten it more. While the hood is off, I would replace it with a slightly shorter belt.
Look and see if the alt can move in towards the engine more without hitting anything.
They are not an original fit, so it may or may not hit something when moved in at the top.
If it hits something like the head, you will need to use the belt it has.

To replace the belt, you will have to loosen the fan belt too.
Don't turn the nut at the rear of the fan shaft, it will break the cast iron sides of the slot.
Use a wrench on the 6 sided place on the shaft, just behind the alt pulley.
Hold the nut if needed to keep it from turning.

The starter is still the original style 6 volt starter. I can read the model number in your pic, that is the number they came with.
People on here convert the charging system to 12 volts and use the 6 volt starter.

Here 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.
They can be removed with the hood on, to use a good light up under the hood is helpful.
The hood is off in your pics, that's easier.
Clean any dirt from around the spark plug bases before removing them, so the dirt doesn't fall into the engine.
Use the starter for the test, not the hand crank, the hand crank is too slow.
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.
Turn the engine over several turns, until the needle on the tester stops going up.
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. :)

cpy911
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Re: New to me cub...no start

Postby cpy911 » Tue Jul 05, 2022 1:29 am

I took apart the switch and cleaned up the contacts. The contacts are definitely NOT new...some wear in there. I am linking a video for you to see the sound it makes for no crank. Also, I felt the negative cable coming off the battery and it was warm and the battery was down about a 1/4 charge. Something electrical may be going on as well. I am baffled.

https://drive.google.com/file/d/1hUJUpo3FUM166MBmQpXgIr13Wux1cxTq/view?usp=sharing

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Glen
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Re: New to me cub...no start

Postby Glen » Tue Jul 05, 2022 5:40 pm

Hi,
I would charge the battery, don't leave it sitting with it low. Use a small output charger is recommended, it may take several hours.

One of the experts on here has said if the contacts in the starter switch are worn so the switch doesn't work right, you can remove the switch, and file the screw holes slightly, so the switch will slide the direction so the posts contact more. The switch has to move the right direction so there is more contact.
If you file the holes the wrong direction, there will be less contact.

Or you can try a new switch.
The people on here say TM Tractor has good quality parts.

If there is an electrical drain, it could be the Delco alternator causing it.
Disconnect it's wires, keep the ends from touching on anything so they don't short.
Charge the battery and let it sit, and see if the drain stops.

You can also test to see if there is a drain with a voltmeter that shows fractions of amps.

The Delco alts can go bad and cause too fast of an electrical drain. :)
Last edited by Glen on Wed Jul 06, 2022 3:12 pm, edited 1 time in total.

cpy911
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Re: New to me cub...no start

Postby cpy911 » Wed Jul 06, 2022 3:01 pm

Looking at the contacts in the start switch, I realized they are really worn...I can see some arcing or sparking when trying to start. Decided to order a new switch. I hope that corrects the problem.

The battery is brand new. I keep it charged up on a float charger.

cpy911
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Re: New to me cub...no start

Postby cpy911 » Wed Jul 27, 2022 10:09 pm

I went ahead and replaced the starter switch. Unfortunately, no crank. I have no idea what to try now. My only guess is to see if the crankshaft still spins around? It seems like something is "stuck". I have shared a video at the following link of what sound I hear.
https://drive.google.com/file/d/1qWQ3xr ... sp=sharing

Any thoughts? Thank you.

Picture of new starter switch.
IMG_6327.JPG

staninlowerAL
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Re: New to me cub...no start

Postby staninlowerAL » Thu Jul 28, 2022 1:58 am

Since you don't have a hand crank, you can remove the spark plugs to relieve the compression and turn the crankshaft using the fan blades to check that the engine is free and not seized. If the C/S turns freely, you have an electrical problem with the starting motor and/or electrical connections in the wiring circuit if the battery is fully charged. You can check the starter motor by removing it from the tractor and see if it will "motor" when the switch is activated when connected to the battery. Expect the starter to move when you try this so secure it temporarily. The starter motor grounds through the frame so you must provide a ground i.e. jumper cable. Since you have an external coil, the magneto internal coil under the square cap is not functioning. It may have been removed. If you remove it be sure to keep the steel bar inside it. The bar is not available for purchase. The wire with the ring terminal next to the starter switch appears to be the OEM electrical "feed" wire from the battery to the electrical distribution system. I can't see what the blue wire go to, maybe the alternator?
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Re: New to me cub...no start

Postby Stanton » Thu Jul 28, 2022 5:55 am

Sorry you're having a difficult time with starting your Cub.

Some good advice already given, but allow me to say that a tractor needs 3 basic things to start/run: compression, fuel, and fire.

Compression: Advice has already been given on doing compression tests (wet and dry) on each cylinder. Compression tester from an auto parts store. Make sure it has an adaptor to fit your spark plug opening size.
Fuel: A mixture of air and gasoline is required to feed into the cylinders via the air intake manifold. Make sure you have good fuel flow into the carburetor. Disconnect the fuel line into your carb and open up the gas shutoff valve/bowl to confirm that you have adequate flow. No dribbling or intermittent flow; it should pour out the same flow diameter as the fuel pipe.
Fire: Your tractor's spark plugs must have a strong, blue and/or white spark that will "jump" from the exposed end of the plug to surface metal (engine) at least a 1/4". A weak spark would be indicated by a yellow color.

The smoke you experienced from the starter is a result of a 12V battery cranking a 6V starter too long. Use short bursts of power to the starter; don't lay on it and keep cranking for long periods of time.

When you get these 3 areas (above) confirmed, get back with us with the results.
Stanton
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staninlowerAL
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Tractors Owned: Cubs: (3)'49's, (1 is for parts), (1)'57 IH Cub LoBoy w/FH, (2)154 Number Series Loboys, (1 is for parts), '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, '47 & '49 Avery V, '53 MM BG (offset), '51 JD M (regular), '56 JD 420C, with Blade and fire plow, '85 JD 850 (Yanmar) w/72" belly mower, '76? Yanmar 2TR15 1500 & Bush Hog SQ42S-2 mower, '78? FORD Dexta, '86 FORD LGT14D & 48" Mower, (2)Cub Cadets & Mowers (MTD), (4) Sears Surburban's, other MTD mowers, Jeeps & other misc. "treasures"
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Re: New to me cub...no start

Postby staninlowerAL » Thu Jul 28, 2022 9:03 am

You did not say how long since the engine has been run. If you have not done so already, be sure to prime the oil pump and check for pressure on the gauge after you get it started. It does not take very long to damage the engine if you don't have oil flowing through the system. If your starter will not "motor" as described in my post above the brushes inside the starter motor could be worn to the point where they are not making sufficient contact with the armature or some other internal problems. A good starter repair shop is a good friend to have. You can have it tested and repaired for less than the cost of a replacement.
Stan in LA (lower AL)
USAF & Reserves, Reg ARMY, ARMY NG (AL)


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