Question on timing

[jdeere86]

Hey all

Been a good while since posted. Tractors have been running good for past several years or so. I have a cub that I cultivated with all summer. I timed her least 5+ years ago and until recently she has been firing up with just couple cranks - once choked and then once partial choke. Towards end of summer it seemed to start a little harder. Anyways went to do annual fluids change yesterday after tractor had been sitting for a couple of months. After a lot of struggling cranking it ..flooding her ..walking away and coming back I got her running. Ran nice drove her round …changed engine oil and transmission,…went to crank start ..no luck again. I get a little putter. Sooo my question is ,,,should I check the timing? Is that something that needs to be re done every so often? I noticed the plugs were a little black so I swapped them

Thank you all

[ricky racer]

The timing doesn't just change, your points could need filing but if I were a betting man, I'd say you've got a partially blocked jet in the carb. I'd start there since it's quick and easy.

[jdeere86]

Good deal. Thank you Ricky - hope to check carb tomorrow - will post what I find. Btw my cub is also a 53’

[Glen]

Hi,
I would check the ignition points also, the more use the Cub has, the more burned the points become.
The points have to be in good condition so the engine will start easily.
The point gap can change over time.
The points need the right gap.

Since the Cub is a 1953, I suppose it has a Battery Ignition unit.
The point gap for a Battery Ignition unit is .020"
You can file them like Ricky said, or replace them if they are burned lots.
I take them out to file them, and use a large file. Wipe off all filings with a clean rag.

[jdeere86]

Thank you Glen. I now feel that I have a more robust plan of attack to troubleshoot tomorrow. Admittedly I’ve only gotten better at routine service over the years and have not gained a whole lot of other know how.

[Glen]

Hi,
Below are pages showing the Battery Ignition unit, and the points, if you need them.

http://farmallcub.com/rudi_cub/www.clea ... age-11.jpg

http://farmallcub.com/rudi_cub/www.clea ... age-12.jpg

[Nelson 634]

Anyways went to do annual fluids change yesterday after tractor had been sitting for a couple of months.

My experience with ethanol fuel without a fuel additive added at refueling is you will have condensate of water from sitting in warm environment in the day time and cooler at night. I find I just drain the water out of the sight glass as well as the carburetor bowl. Which usually solves the problem until I let the tractor set for several weeks. If you have access to non ethanol fuel it does not have this problem. I have seen reported on this forum if your tractor is "Shed Kept" this tends not to be a problem either. This is an easy fix. I'd try it first, before a mechanical one.

[jdeere86]

It got above freezing today so I went out to work on the cub. Took the main jet out of carb - cleaned it. Checked the points and set the gap. Went to crank - doesn’t sound like it wants to fire at all…

[Don McCombs]

Did you check the fuel flow while the main jet was removed? Are you getting a bright blue/white spark at the plugs?

[jdeere86]

No - should have and will check the fuel flow. I pulled a spark plug — it was already covered in soot — had just changed put them in brand new — plugged in the wire and rested plug on block…cranked it,…no spark.

[jdeere86]

Pulled the main jet again and turned fuel on…steady stream. Did notice the jet had a little gunk in it - cleaned out. Let’s see if I can pose this question correctly - when it comes to setting the point gap is the gap set in the position as soon as you hear magneto click when turning over ?

[Usmc0861]

on the high part of the lobe is where the gap is set

[jdeere86]

Hm not quite sure what the high point of the lobe means…I see that’s what they say in the manual.

[staninlowerAL]

Hm not quite sure what the high point of the lobe means…I see that’s what they say in the manual.

This refers to the highest point of the mag/distributor shaft where the rubbing (contact point) of the points pushes to open the points (.013 for a mag, .020 for a distributor). Maybe these pictures from the service manual will help explain it. The lobe is called cam in the 2nd picture.

[Glen]

Hi,
I don't know if the Cub has a magneto, or a Battery Ignition unit.
They are 2 different units. They use different point gaps, like was said above.

The movable point, the point on the right side, has to be as far as it will move to the right, to set the point gap.
Turn the engine slowly using the fan, until the moving point is as far to the right as it goes.
Then the moving point is on the high part of the cam.
Then set the point gap.

If you have a magneto, you can lose the timing of the rotor to the magneto, if you turn the engine too far, with the cover off the magneto, that holds the rotor.
The Cub operator's manual has pics and info of the points in the magneto.