Timing on 74 Cub

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Floridaboy
Posts: 15
Joined: Fri Nov 30, 2018 4:52 pm
Zip Code: 34639
Tractors Owned: 1974 Original owner

Timing on 74 Cub

Postby Floridaboy » Tue Apr 02, 2019 7:19 pm

Put on the new manifold gaskets and installed new points, condenser and rotor cap. Seems that the timing is approx. a half turn off now. I have loosened the distributor in the past and twisted slightly to time but did not know what to do when timing is so far off. Thanks in advance for the help. MLB

Eugene
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Re: Timing on 74 Cub

Postby Eugene » Tue Apr 02, 2019 9:11 pm

Does tractor run?
Did you remove the distributor to install the points?
Did you set the tractor on #1 cylinder, TDC before installing the points?
I have an excuse. CRS.

Floridaboy
Posts: 15
Joined: Fri Nov 30, 2018 4:52 pm
Zip Code: 34639
Tractors Owned: 1974 Original owner

Re: Timing on 74 Cub

Postby Floridaboy » Tue Apr 02, 2019 10:03 pm

no, tractor does not run
Did not remove the distributor to install points.
Did not set on TDC before installing points.

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Glen
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Re: Timing on 74 Cub

Postby Glen » Tue Apr 02, 2019 10:27 pm

Hi,
It should still run, if you didn't remove the Battery Ignition unit, or change the timing.

When changing ignition points, the rubbing block on the right hand point, has to be on the high part of the cam, the 4 sided piece that opens the points, so the points will open. Then set the gap to .020".
The engine won't run if the points don't open and close, when the engine turns over.

Below are pages from the Cub owner's manual showing the points for a Battery Ignition unit, starting on the right side of the page.

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

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

Number 1 cylinder on the cap is at the upper right, unless the distributor is turned from the original position. Check the spark plug wiring order.

After checking the above items, if it won't run, you could have gotten a defective condenser. Try putting the old condenser in and see if it runs.

When it runs again, the engine should be timed with a timing light, the owner's manual says.

outdoors4evr
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Re: Timing on 74 Cub

Postby outdoors4evr » Wed Apr 03, 2019 7:13 am

Sounds like a 'start over' moment.
Rotate engine to #1 cylinder at TDC (Compression stroke)
Reset distributor so that the #1 tower is pointed to the 1:00 position.
Verify that the rotor is pointing toward that same 1:00 position.
* Points should be closed.
Rotate engine so points open to max (should be about 1/4 turn of the crankshaft) and set the gap as Glen mentioned.
Put distributor cap back on and get it running. Set timing with a timing light.
184 w/ Creeper & 3-Point
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Floridaboy
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Joined: Fri Nov 30, 2018 4:52 pm
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Tractors Owned: 1974 Original owner

Re: Timing on 74 Cub

Postby Floridaboy » Wed Apr 03, 2019 2:02 pm

Set to TDC. Rotor cap is pointed almost straight down. How do I reset the distributor? I've loosened the distributor to turn slightly in the past but never like this. Any suggestions on how to? thanks, MLB

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Glen
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Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
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Location: Wa.

Re: Timing on 74 Cub

Postby Glen » Wed Apr 03, 2019 3:57 pm

Hi,
It's usually easy to get them to run.

Below is a pic of the rotor, from TM Tractor. If the engine is at number 1 cylinder TDC, the end of the rotor that is at the left in the pic, should be pointed at the number 1 position on the distributor cap.

The Cub owner's manual says to determine number 1 TDC, remove the number 1 spark plug, and put your thumb over the hole, turn the engine until you feel pressure coming out of the hole, then check the timing marks, and slowly turn the engine until the marks are aligned.

Below is a page from the Cub service manual showing the timing marks a 1974 Cub would have. Align mark number 1 in the pic with the pointer. Maybe you knew this already.
They are talking about other subjects on the page, use only the pic, and words under it.

http://www.farmallcub.info/manuals/gss- ... 001-43.jpg

If after doing the above, the rotor still points to the wrong position, you will need to remove the 2 bolts and clips holding the distributor to the base. Then pull the distributor out of the base, until the gears are free, then turn the shaft and rotor until it is pointed to the number 1 position on the cap, put the distributor in again, and put the clips and bolts in again.
When it is out, you could check the gear for condition, clean it if needed, and put some grease on the teeth.
When putting it in, the distributor is originally turned so the small post on the side of it is facing to the right. Then number 1 on the cap is at the upper right.

When it runs again, the Cub service manual says use a timing light to set the timing. It should be set so the number 1 mark in the pic above aligns with the pointer at slow idle speed, 500 RPM. :)
Attachments
Cub Rotor.jpg
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Last edited by Glen on Wed Apr 03, 2019 6:18 pm, edited 1 time in total.

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MiCarl
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Re: Timing on 74 Cub

Postby MiCarl » Wed Apr 03, 2019 5:58 pm

Floridaboy wrote:Set to TDC. Rotor cap is pointed almost straight down. How do I reset the distributor? I've loosened the distributor to turn slightly in the past but never like this. Any suggestions on how to? thanks, MLB


Are you sure it's on the compression stroke? Rotor will point down at the end of the exhaust stroke.
1944 Farmall H
1948 Farmall Cub
1994 Speedex 1631

Eugene
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Re: Timing on 74 Cub

Postby Eugene » Wed Apr 03, 2019 6:02 pm

MiCarl wrote:
Floridaboy wrote:Set to TDC. Rotor cap is pointed almost straight down. How do I reset the distributor? I've loosened the distributor to turn slightly in the past but never like this. Any suggestions on how to? thanks, MLB
Are you sure it's on the compression stroke? Rotor will point down at the end of the exhaust stroke.
Since tractor previously ran and you did not remove the distributor, you are on TDC #4 cylinder not #1 cylinder TDC.
I have an excuse. CRS.


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