Cub hard starting

[JBIRD1959]

Cub been sitting for a month. Started right up, ran like a champ. Ran in thru all 3 gears, no issues. Shut off, went to start again after 1/2 hour, would not start. Notices Zenith carb mounting bolts were loose, tried to tighten, the holes in carb were stripped. Bought new carb off internet, installed and Cub started right up ran like a champ, drove it around for a hour, shut off and went back to start, would not start. Checked to see if getting spark, looks good, charged the battery, let set for 2 days, went out this am, took a while but got started, ran like a champ, shut off, will not start again. Its getting good fuel, distributor cap looks good, points don't look bad either. I did remove the float bowl and clean up everything, added new fuel, and still hard starting. Owned Cub for 1 year, never had this problem before. Any suggestions? Thanks

[Glen]

Hi,
The spark should be strong and blue. A yellow spark is weak, and needs improving.
You could try filing the points, they have to be in good condition for the engine to start good.
They are usually hard metal, I take them out and hold one at a time on a hard surface, and use a large, sharp flat file on them. Wipe off all filings with a clean rag.
If they are worn down much, new points are better.

Below is a listing at TM Tractor for new points and condenser, you can see the pic of them if you want.

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

[k hutchins]

My 1st guess would be a bad coil. When they get worn, they heat up and will usually cause a stall. Then won't allow you to restart until it's cooled down.
Another issue people have had is that after getting the engine hot (like running it for an hour) they shut it down, then try to start it with the throttle back at idle. I have the best luck leaving the throttle at 1/2 or higher on a hot engine.
Good luck.

[JBIRD1959]

Thanks Gentlemen for the help. Will try the new plugs and go from there.

[tst]

before replacing parts make sure you have a good blue spark

[JBIRD1959]

Went to Steiners today got tune up parts, points, condenser, distributor cap, got all together, I have spark at points, no spark at plugs. I did roll magneto to hear click, pointed everything to number 1 cylinder. Took apart ran thru sequence again , spark at points no spark at plugs.

[Rick Spivey]

Could be a bad coil. I may be confused, but seems like you have several posts on here that may indicate bad coil with various symptoms. The spark at points would indicate the coil's primary wiring is intact and functioning, but no guarantee of the secondary winding being intact, which is what provides the spark to the plugs.

[Glen]

Hi,
Too bad it is not working.
I suggested servicing the points because they have to be good, and they cost less than a new coil.
The condenser being bad can make it not have spark too.

The coil may have quit, like was said above. Or the spark plugs could be bad, and won't fire.
You could try checking the spark by removing the center wire from the distributor cap, and holding it by the insulation, with the metal end 1/4" away from a bare metal ground on the engine, turn the ignition switch to on, and run the starter. The spark should easily jump the 1/4" gap, and be blue.

You didn't say what year Cub you have, I guess it has a magneto, you said.
If it still has the original style coil in the magneto, TM Tractor has a listing for those, you can look at it.
The coil has a metal bar that goes through the center of it, reuse the bar with the new coil.
The small wire on the coil has to be connected like the old one is, remove the cover over the points to see it, I think.

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

Below are pages from the Cub parts manual, showing the magneto, if you need them.

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

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

When you have the cover over the points off, you could remove the cover that holds the rotor on, and clean the area, and put in new grease on the gears. The owner's manual says to do that.
Check the rotor gears timing marks also. They should be aligned, like the pic below shows.
Sometimes people put them together wrong, with the marks not aligned, because they have the magneto timed wrong, but originally they should be aligned.

[JBIRD1959]

Thanks so much for the help. Glen the picture you posted is what I have. I will go check for spark at the distributor cap. And recheck position of rotor.

[JBIRD1959]

Well another day and no luck. I got good spark from magneto, pull spark plug and only sparks once than no more. New plug wires today, new sparks plugs, I even pulled oil pan to make sure no major issues , all is good. When I got tune up kit from Steiners it had the wrong rotor, still using old one. Not sure if that is why no fire or intermittent spark at plugs. Went thru it all again gap at points, rolled engine till I hear magneto click, set rotor to number one, and have done this a few times. Still coming up with no spark at plugs.

[Don B.]

Although I don't really think it's your problem here, do make sure the plug wires are old fashioned copper core rather than more modern resistor wires.
Magnetos don't like the new fangled ones. Learned that at a Barnyard Bash.
I found out the hard way. They made the spark very erratic. Just enough to make you scratch your head.

[Glen]

Hi,
How are you testing the spark at the spark plugs, if you have the spark plugs out, and are looking for spark to jump the gaps, the threaded area, or bottom, needs to be touching well on a bare metal place of the head. If the head is painted, and has no bare metal, the plugs won't ground, if they are on the paint, and there won't be any spark, or an intermittent spark.

The rotor will work if it still looks good, and not burned, and the gear on it is still good. You could sand it's contacts with fine sandpaper if needed.
A new magneto rotor costs some money. Below is a listing at TM Tractor for it.

http://www.tmtractor.com/new/el/294fp.htm

[Rick Spivey]

Went thru it all again gap at points, rolled engine till I hear magneto click, set rotor to number one, and have done this a few times. Still coming up with no spark at plugs.

This description is just unusual enough to cause me to question what you are doing. So some basics. The rotor is timed to the pinion by aligning small cast scribe line (rotor) to dot or triangle, etc. on pinion. Once that is done you should never change that relationship again. Then the drive lugs of the magneto will only line up to the governor one of two ways. If the governor drive gear is not lined up correctly, you are essentially dead in the water until that is corrected. The two lugs should be at roughly 2 and 8 o'clock positions, there are plenty of posts on here showing the correct alignment. Install the magneto with the rotors close as possible to number 1 tower on distributor cap. Lastly, you should rotate the body of the magneto as far as possible into the block, align the pointer on the front of the engine cover to the notch on the pulley, and then rotate the magneto away from the block until the impulse snaps. Lock it down right there and you are in time. At no point would you move the actual rotor in response to the impulse click.

[JBIRD1959]

Update 11/5/2018. Its the magneto!!. Decided to pull mag and tear apart. Not gonna learn any younger right? Coil clip on side for mounting was broken off, cowl spring was found all twisted up. I watched a video on Steiner's with the young girl rebuild a mag, that was a very humbling. I want to thank each and everyone of you for the help and advise, my first Cub and not going to be my last. Love these tractors. And I will be back asking question for the next issue. HAVE A GREAT DAY.
.

[JBIRD1959]

Got the springs needed to finish the rebuild of the mag. Installed on tractor, started right up ran excellent. And it started to snow this am. Thanks again for all the help.