Cub Carburator Adjustment

[Eugene]

Anyone out there can tell me if its easy to remove the breaker chamber cover while the electronic ignition unit is still mounted and timed to the cub? I just want to get in there and check the points but I am too lazy to retime.

Timing light. Easy check and adjustment. No nead to initially remove any parts from the distributor.

[farmergiffIV]

Anyone out there can tell me if its easy to remove the breaker chamber cover while the electronic ignition unit is still mounted and timed to the cub? I just want to get in there and check the points but I am too lazy to retime.

Timing light. Easy check and adjustment. No nead to initially remove any parts from the distributor.

Please explain more. I have never heard of a timing light. My goal is to check the the point on the breaker arm. I just went through the spark plugs and will double check my work but for some reason all plugs are fine but the 4th plug sometimes misses spark.


EDIT: When I hold down the electric starter for 3-5 seconds, the coil occasional misses a spark, hmmm?

[Eugene]

Please explain more. I have never heard of a timing light.

Really? If you own machinery/tractors you need one and need to know how to use it.

An internet search which will tell you what a timing light does, and how to use one.

You can search this site and there are a number of posts telling you how to hook one up to your tractor.

Edit: I shouldn't have phrased my first sentence is such a manner. Old age, I guess. I've been wrenching engines for 60 plus years. Taught mechanics at tech school and high school level. As previously stated, poorly phrased.

Attend a Cub fest or two. Very educational for Cub owners. Have the guys show you how to time and tune up a Cub engine. There are a number of steps/procedures to tune up a Cub engine, but, they can be conducted with a few basic tools.

While on the podium, diagnose the problem. Did I say DIAGNOSE THE PROBLEM. Darn, I use to say that 3 times during a lecture while pounding on the podium. Saves time, money, and aggravation when things don't work out.

[farmergiffIV]

Please explain more. I have never heard of a timing light.

Really? If you own machinery/tractors you need one and need to know how to use it.

An internet search which will tell you what a timing light does, and how to use one.

You can search this site and there are a number of posts telling you how to hook one up to your tractor.

The timing light will tell you if the point on the breaker arm is at proper length? Wow!

[Eugene]

No, not really. The timing light is used to tell you if the ignition timing is correct in relationship to the piston being at TDC.

You can have the correct point gap, but still need to adjust the ignition timing - - - basically turning the distributor until the spark is spot on.

On most slow turning tractor engines, the actual point gap has to be close to the factory recommendation. You then adjust the distributor to get the spark to occur at piston TDC.

Accurate ignition timing is critical. A part of a degree or more in advance of the piston reaching TDC, and the engine will be hard starting. A degree or two after TDC and the engine runs ok but lacks power.

[Glen]

Hi,
A timing light is used in the automotive, truck, and tractor industry to check and set the engine ignition timing, so the spark plugs fire when the crankshaft and pistons are turned to the right positions.
Every car or truck or tractor with a distributor should have the timing checked with a timing light.
Below is a timing light from Amazon, you can look and see what it is. The light is in the front end of the unit. After connecting the wires, 2 to the battery, and 1 over probably the number 1 spark plug ignition wire, you point it at the timing marks on the front pulley of the Cub, with the engine running, and the light flashes and shows you where the timing is set to.
The lights probably come with instructions.


https://www.amazon.com/Tooluxe-20724L-A ... ming+light

I'm not sure if your Cub has a magneto, or a Battery Ignition unit.
There is a page in the Cub service manual about timing the engine with a timing light.

[farmergiffIV]

Believe it or nor these two cubs are my first mechanical projects in relation to machine maintence besides an old lawnmower... I will check out these timing lights online and consider checking out it. the '53 has a battery ignition unit. Still I am wondering if there an easy way to access the breaker arm without taking the unit off the tractor. Is it all three screws that must be removed to access the breaker arm?

[Don McCombs]

No screws must be removed to access the points on a battery ignition unit (distributor). Which do you have on your tractor...

A. J4 Magneto


or

B. Battery Ignition Unit


This is what the battery ignition unit looks like with the cap, dust cover and rotor removed...



Photos courtesy of TM Tractor Parts

[Eugene]

He is talking about 3 screws, so it must be a magneto.

If you haven't done so, down load the operator's, parts and service manuals, free, top of page, Quick Links.

Timing light. They are readily available. Check prices at your local auto parts store, Harbor Freight, Tractor Supply, or your local farm and ranch store. Local purchase may be cheaper when you figure in postage and handling.

Edit: Farmergiff, there is a very specific way the magneto is assembled. Be sure you understand how to set the engine on TDC #1 cylinder and how the rotor fits.

[staninlowerAL]

Eugene is referencing GSS 1012. It will explain in detail both the battery ignition and magneto systems maintenance, service and repair.

[farmergiffIV]

No screws must be removed to access the points on a battery ignition unit (distributor). Which do you have on your tractor...

A. J4 Magneto


or

B. Battery Ignition Unit


This is what the battery ignition unit looks like with the cap, dust cover and rotor removed...



Photos courtesy of TM Tractor Parts

The '53 has a battery ignition unit, do you have to take it off to the engine to check out behind the dust cover? I haven't taken mine off yet and I rather do less if I just need to check the breaker arm.. Thanks I am more familiar with the Magneto on my '48...

[Don McCombs]

No. Take the cap off. Take the rotor off. Lift the cover with the two small tabs.

[Glen]

Hi,
You can leave the Battery Ignition unit on the engine to file or replace the points.
I use a chair and sit next to the engine, you need a good light to see in the Battery Ignition unit, and I put a large towel on the ground to catch any small screws I might drop.
You need a short screwdriver, and an 11/32", I think, open end wrench to loosen the nut that holds the end of the points spring.
The points need replacing if the surfaces are burned or really rough. They can be filed if they are not burned a lot. Burned or dirty points can make the engine start hard, and run bad.
To file them, I take them out and hold them one at a time on a solid surface, and file them with a large flat file.

The Battery Ignition unit is different than a magneto, there is no plate with the 3 screws to remove to get to the points.
Below is a page from the Cub owner's manual showing setting the points.

http://farmallcub.com/rudi_cub/www.clea ... e%2041.jpg

Below is a listing for new points and condenser at TM Tractor, if you want to see them.

http://www.tmtractor.com/new/el/367fp.htm

NAPA has new points too, they are CS1600.

Below is the 1955 Cub owner's manual, it has the Battery Ignition unit in it. There is a table of contents on page 1.

http://farmallcub.com/rudi_cub/www.clea ... index.html

[Eugene]

You will need a feeler gauge to test and reset the points gap.

[farmergiffIV]

The cub is running real smooth now. I adjusted the spark plug gaps, the points gap on the battery ignition unit, and the carburator float adjustment. I am not getting any flooding really now, just 1/3-1/4 choke when starting up the tractor and it'll start up nearly everything time just after a second or two on the starting rod.... Thanks for the tips