generator

[pett3227b]

yeah thats my main problem the cub looses power after running for 30 minutes. Runs longer if cold weather. gonna replace the coil. thanks

[Nelson 634]

Before you spend money on a coil check the tightness on all connections inside and out of dist. Also consider replacing condenser. Much cheaper. Having said that,

yeah thats my main problem the cub looses power after running for 30 minutes. Runs longer if cold weather.

may point to a bad coil. Its just cheaper to check connection and condenser.

[Glen]

Hi,
I would replace the ignition points and condenser, if they haven't been replaced lately.

The points get old and burned from use, and it can affect how the engine starts and runs.
They are cheaper than a new coil. You could replace them first, and see if it works right, if it doesn't then replace the coil.

Below is a listing at TM Tractor for points and condenser, you can look at the pics.

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

The 1949 Cub owner's manual has magneto info, and shows how to get to the points, you have to remove the plate that the rotor is on.
It's better to turn the engine to number 1 cylinder TDC before removing the plate.
The rotor should be facing about straight up, if your cap is wired the original way, with number 1 cylinder at the top of the 4 connections.
Below are pages with info.

http://farmallcub.com/rudi_cub/www.clea ... age-30.jpg

http://farmallcub.com/rudi_cub/www.clea ... age-31.jpg

Tighten the nut at the end of the points spring gently, there is an insulation there in the side of the magneto, it can break if the nut is tightened too much.

Don't turn the engine while the plate is off, you can lose the timing.
Turn the engine with the fan, only enough to open the points fully, on the high place of the cam that opens the points, when replacing the points, and setting the point gap.

Below is TM Tractor's listing for a new coil.
The coil has a bar that goes through the center of it, you have to save it, and reuse it with the new coil. Some of the bars fit tight in the coil.
You have to remove the plate the rotor is on to get to the end of the small wire on the coil, to replace the coil, so I would replace the points and condenser too, since the plate would be off.

http://www.tmtractor.com/new/el/713fp.htm

There is one magneto coil, for either voltage of battery, the magneto is not connected to a battery.
Don't connect any battery to the magneto.
The magneto makes it's own power without a battery.

Since you would have the plate off, you could grease the rotor gears, like the owner's manual says to do. Remove the 2 screws holding the cover on, and clean the old grease out.
Check the condition of the gears, if the teeth look worn much, the rotor and drive gear should be replaced.
TM Tractor has new ones.
The gears have timing marks, they should be aligned.
Put new grease on the gears.

Below is a pic showing the rotor gears, and timing marks.

[pett3227b]

I am currently watching videos on how to replace the coil. I will check the connections and replace the points and condenser. I remember reading some posts dealing with all the electrical system and I remember some talk about a positive ground system. If a cub is converted to 12 volt is the direction of current also switched? My 12 volt battery is currently grounded on the negative terminal. Is this any evidence that My cub has been converted to 12 volt or could it still be 6 volt? Just a thought. I have contacted a guy who rebuilds generators and alternators and he has told me that he would be able to look at the windings and tell me if the gen is 6 or 12 volt. Working on it.

[Glen]

Hi,
All 6 volt Cubs were originally positive ground.
Cubs were 6 volts until mid 1964.

12 volt systems are commonly negative ground.

Someone could have connected the 12 volt battery with negative ground, and not changed anything else on the Cub.
But on your Cub, something was changed, the Relay, or voltage regulator, whichever it has, is on the engine.
You didn't say if you counted the number of wire connections on the Relay or regulator.
I wrote before they have different numbers of connections.

The current direction is only changed if the system is positive or negative ground, not by what the voltage is.

Be careful that you are watching a video that is showing the right magneto, they are model J 4.

It is not hard to replace the points and condenser, and the coil.

Below are pages from the 1949 Cub owner's manual, showing how to get to the points and condenser, and replacing them, and setting the point gap.

http://farmallcub.com/rudi_cub/www.clea ... age-30.jpg

http://farmallcub.com/rudi_cub/www.clea ... age-31.jpg

This page tells how to time the magneto to the engine, if you need that.

http://farmallcub.com/rudi_cub/www.clea ... age-32.jpg

Below are pages from the Cub parts manual, showing a Cub magneto.

http://www.farmallcub.info/manuals/cub_ ... 012-22.jpg

http://www.farmallcub.info/manuals/cub_ ... 012-23.jpg

[pett3227b]

glen, I looked again at the voltage regulator or relay whichever it is. It is not curved on the bottom. There are 4 spots where wires can be connected. only 3 are currently connected to anything. that is not including the ground wire. the ground comes out the bottom and is connected to the block.

[Glen]

Hi,
Thanks for saying how many wire connections the voltage regulator has.
It sounds like it has a Cub voltage regulator.
Someone changed it to a regulator evidently, which came out in 1950 on Cubs.

I would suggest moving it to the IH mounting plate that I wrote info about at my 3rd post, on page 2 of this post. If you use the Cub for working, the reg can get too hot on the engine.
You will have to move wires some to do that.

It looks like in your pic on page 1 that the L post on the regulator is not connected, if the connections are the same as the reg I have. The L post powers the lights, I think the reg works without the post connected, but I'm not sure.
Someone could have connected the lights somewhere else for power.

They originally have no ground wire, the reg grounds to 1 mounting bolt, there is usually a small wire made on the reg going to 1 mounting.
If you take the reg off, it may say the voltage on the bottom, and the ground, Pos, or Neg. They are usually just stamped on with ink.
Below is a pic from Brillman of a Cub voltage regulator.

[Eugene]

The L post is for lights, I think the reg works without the post connected, but I'm not sure.

L post is connected to the battery post within the regulator. Regulator will function without the L post wired to anything.

L post, depending on the schematic source could stand for lights or load.

Edit. Suggestion, again. Single wire 12 volt alternator and an external 12 volt ignition coil for the magnetio.

[Glen]

Looking at the wiring diagram in the 1955 Cub operator's manual, with a magneto, the wire from the L post on the regulator goes to a junction block on the back side of the dash, then to the fuse, then to the light switch.
They used the fuse for the lights, in the bottom dash hole, after the voltage regulator came out.

With a Battery Ignition unit, the wire from the L post on the reg goes to the ignition switch, and powers the ignition coil, and the lights.

I don't know what the L stands for, it could be either one you said.

[Glen]

Hi,
I sent you a PM.

[Cubfriend]

looking at the generator pic it has a red tag, so it appears someone put a 12 volt generator on it ????, do not know about the # he gave, and yes the regulator is laying on the head

I wonder if the red was some overspray from painting the tractor at one time in the distant past. Protected by the hood could remain for generations.