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Farmall Cub • View topic - 50's Cub timing pulley marks - magneto

50's Cub timing pulley marks - magneto

Thu May 16, 2013 10:34 am

Are there two sets of marks on timing pulley - one for distributor system and another for magnetos? (Boss with degrees vs two notches on pulley?) If there are two sets of marks, which do I use for magneto ? (Degree scale clear on my pulley...Notches, if any, are not so obvious)
Governor casting was cracked so silver soldered crack (worked fine) but now cannot get governor back where it goes to right position to drive magneto & timing. Help! (Would timing lite fire even if magneto was out by 180 degrees?)

Re: 50's Cub timing pulley marks - magneto

Thu May 16, 2013 10:43 am

On an original pulley for a 1950 Cub, there should be only one mark on the pulley. However, they often get replaced with later pulleys with two notches. If you are static timing a mag (or a distributor) and if the pulley has two marks, you want to set the pulley so that the SECOND mark lines up with the pointer. The first mark would show the full advance.

On putting the governor back in the tractor, there are punch marks on the governor gear and on the idler gear inside. It helps to mark the teeth (or valley) with white out or some other marking device so that you can see it when you are putting the governor back in the tractor. With a mag, it is crucial to get the governor at the right place in order to set the mag timing.

Also, on the mag side of the housing where the governor goes in, there is a punched line at about 2 o'clock. The slots in the governor need to line up with that punch mark...just another way to make sure that it is in the right spot. If you don't get the governor timed correctly, you will not be able to get the mag timed correctly...

Mike

Re: 50's Cub timing pulley marks - magneto

Thu May 16, 2013 11:31 am

Good info from Mike. Also, manuals are posted at the top of this page. Welcome to the best Cub website on the planet.

Re: 50's Cub timing pulley marks - magneto

Thu May 16, 2013 12:14 pm

Would timing lite fire even if magneto was out by 180 degrees?
Yes, timing light flash is triggered by the "spark", "high voltage", in the plug wire. The timing light doesn't know or care what the ignition timing is, just indicates a spark.

You will need a 12 volt DC source for most timing lights.

Re: 50's Cub timing pulley marks - magneto

Fri May 17, 2013 11:17 am

Hengy
Thanks! Extremely helpful! Cannot ID proper mark on pulley... If I get #1 at TDC can I put my own mark on pulley so I can get timing right? Does magneto fire at TDC... If so maybe I can try different gear meshes to get timing light to fire when it is supposed to...(TDC on #1) Maybe I don't see so well anymore but could not find punch marks on two gears...

Re: 50's Cub timing pulley marks - magneto

Fri May 17, 2013 11:53 am

Can you see a punch mark on the governor/distributor housing? It is visible on the face of the housing facing the operator's platform. Check you pulley again... I cannot imagine that there is not some kind of mark on the pulley...they all came with one for SURE! (unless it is some kind of aftermarket pulley that I am not aware of) If the tractor has been painted in the past, it is possible that the pulley was "well painted" and the paint filled in the mark. If you can look at the valves on the tractor's left side, you can get "close" to #1 TDC. That is when both intake and exhaust valves are closed. Alternatively, remove #1 spark plug and put your thumb over the hole. When you feel pressure on your thumb, that is compression stroke on #1 piston. Then look at your pulley again. The mark should be there.

That is the only way that I can see to get the tractor TRULY at TDC. Then aligning your governor with the punch mark on the housing or getting the punchmarks on the gears to line up is a relative breeze after that point!

Mike

Re: 50's Cub timing pulley marks - magneto

Fri May 17, 2013 1:21 pm

You said something about "degree scale" on the pulley?

I've never known a Cub front pulley to have a degree scale. It should only have one or two fairly significant V-notches, depending on the age of the tractor.

Re: 50's Cub timing pulley marks - magneto

Sun May 19, 2013 8:29 am

You guys are great! I did what you said and it runs beautifully! Governor had big crack.... Silver soldered it and it worked... There is small locator pin in casting for mating and somebody misaligned it, and when bolted governor down created crack... (Could not align gears with punch marks... tried 3 times) Also, Youtube has a video "How to static time magneto on Cub" which was great help... Thanks for your help again.... I am sure I will be back to you with the next problem!

Re: 50's Cub timing pulley marks - magneto

Sun May 19, 2013 11:46 am

There are 2 places where the marks have to be aligned, on at the idler gear to crank junction, and one at the idler gear to governor junction. The go " 1 mark to 1 mark, and 2 marks align with 2 marks" Many people get them worng and even though the governor to idler looks correct, the timing is still wrong.

Re: 50's Cub timing pulley marks - magneto

Sun May 19, 2013 6:04 pm

Guess I missed this thread....

The CBoK aka Cub Book of Knowledge and the How To Forum has all the information as in How To's both static and video to help. In fact the How To Static Time a Mag on youtube is most likely WisconsinCubMan aks Hengy aka Mike's video

Image to Farmallcub.com :big smile: Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information, it will point you to :arrow: the Welcome Wagon wherein you will find links to many useful sites and topics. One of which is the Cub Manual Server. Enjoy!.


Glad you got it solved.