hey guys need help again so dont laugh:)

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johnnygo
Posts: 11
Joined: Tue Jun 15, 2021 11:25 am
Zip Code: 34428

hey guys need help again so dont laugh:)

Postby johnnygo » Wed Sep 22, 2021 4:04 pm

ok dont laugh but i know nothing about flathead motors, i have a 48 cub c-60 motor and im putting on new wires,cap,rotor,points and condensor, since i dont have a number 1 piston to

look at top dead center, can any of u (please in laymens terms) explain to me step by step how to get the rotor to point to number 1, so i can make sure the wires are going to

the corresponding plugs? and what is the right point gap? i was told 13 but not sure......and any other helpful hints u got.........just did a 6 volt to 12 volt conversion along with the above and im getting fire from the coil to the plug even thou its sounds like it wants to start, its not any help is appreciated, remember im no mechanic i just follw u guys and usaully get thru it. thnx in advance

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Glen
5+ Years
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Posts: 5063
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: hey guys need help again so dont laugh:)

Postby Glen » Wed Sep 22, 2021 6:12 pm

johnnygo wrote:since i dont have a number 1 piston to
look at top dead center,

Hi,
The Cub engine has 4 cylinders, the number 1 cylinder is the front one on the engine.
They are numbered 1, 2, 3, 4, front to rear.

A 1948 Cub originally came with a magneto, some Cubs have been changed to a Battery Ignition unit, which came out during 1950.
You need to identify which one you have.
The point gap for a magneto is .013"
The point gap for a Battery Ignition unit is .020"

Below are pages from the 1949 Cub owner's manual, showing the magneto, you can look at the pics and see if it is what your Cub has.
Use the info for what you are doing, there is more info you don't need now.

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

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

The page below shows how to install and time the magneto to the engine.
At 2 it tells how to find TDC for number 1 cylinder. Use only 2 on the page, since you are not setting the timing now.
The engine will be at number 1 cylinder TDC, doing what it says at 2.

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

Originally number 1 on the magneto cap it at the top position.
The rotor should be pointed about straight up when the engine is at number 1 cylinder TDC.
It may not be quite straight up because of the impulse coupling the magneto has, it winds up and makes the snapping sound.

The engine firing order is 1, 3, 4, 2
You can see in the pic on the 3rd page, they are numbered going clockwise around the cap, looking ahead from behind the cap.

The points, condenser, and cap are the same for both units. The rotors are different.
The rotor on the magneto is gear driven.
Below is a listing for a new one at TM Tractor, you can look at the pics.

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

If the Cub has a Battery Ignition unit, you need info for it.

Below is a page from the 1955 Cub operator's manual showing a Battery Ignition unit, you can see if yours has one. :)

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

Clemsonfor
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Joined: Sun Nov 10, 2019 5:14 pm
Zip Code: 29848
Tractors Owned: Yanmar YM2000
Yanmar YM186 (non running)
1952 Farmall Cub
Circle of Safety: Y
Location: Greenwood County SC

Re: hey guys need help again so dont laugh:)

Postby Clemsonfor » Wed Sep 22, 2021 8:13 pm

There definitely is a #1 cylinder. There is a #1 regardless if it's flathead or overhead valves. Glen has a very detailed answer to figure it out. I didn't see him post the plug gap which is what I think you were looking for, he did post the point gap. I would be just guessing at what plug gap is, I can't remember what it is at this point. I would just look it up in the manual or on here if i needed to quote it.

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Glen
5+ Years
5+ Years
Posts: 5063
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: hey guys need help again so dont laugh:)

Postby Glen » Thu Sep 23, 2021 12:03 am

Hi,
Below is a page from the 1949 Cub owner's manual, it says the spark plug gap was .023" - .027" then.

http://farmallcub.com/rudi_cub/www.clea ... age-29.jpg

The newer manuals say .023" for either ignition system.

johnnygo
Posts: 11
Joined: Tue Jun 15, 2021 11:25 am
Zip Code: 34428

Re: hey guys need help again so dont laugh:)

Postby johnnygo » Fri Sep 24, 2021 10:47 am

wow 1st off thnx for all the info i think its exactly what i was looking for.........so my rotor comes off, so that means mines an electrical ignition? ive included some pix of both my toys and what i have ignition wise on this one, and once again thnx for any advise and future help :) and just in case i didnt tell u in original post im changing from 6 volts to 12
Attachments
rotor.jpg
dist6.jpg
dist4.jpg
dist3.jpg
dist2.jpg
dist.jpg
dist.jpg (17.06 KiB) Viewed 360 times

User avatar
Glen
5+ Years
5+ Years
Posts: 5063
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: hey guys need help again so dont laugh:)

Postby Glen » Fri Sep 24, 2021 7:27 pm

Hi,
That is a Battery Ignition unit on the Cub.
Someone changed it to that in the past evidently.
The number 1 spark plug wire originally goes to the upper right post on the cap.

Below is info for the Battery Ignition unit.

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

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

The unit is originally timed so the post on the side of the distributor faces straight to the right.
Then the number 1 spark plug post on the cap is at the upper right.

Below are pages from the 1955 Cub operator's manual, showing wiring routing, in the center pic on the 1st page, if you need it.
The 2nd page shows what the numbers on the 1st page are.

http://farmallcub.com/rudi_cub/www.clea ... age-38.jpg

http://farmallcub.com/rudi_cub/www.clea ... age-39.jpg

The Cub service manual says set the ignition timing using a timing light, when the Cub has a Battery Ignition unit.

johnnygo
Posts: 11
Joined: Tue Jun 15, 2021 11:25 am
Zip Code: 34428

Re: hey guys need help again so dont laugh:)

Postby johnnygo » Sat Sep 25, 2021 9:24 am

hey glen, thnx for all that i think that will get me on my way, i`ll let u know how it goes, thnx for all the good info. troy

johnnygo
Posts: 11
Joined: Tue Jun 15, 2021 11:25 am
Zip Code: 34428

Re: hey guys need help again so dont laugh:)

Postby johnnygo » Mon Sep 27, 2021 5:30 pm

hey glen, got it running today turned out i did have my wires wrong, and u were right number 1 on compression stroke was just about straight
up at 12/oclock, anyway got that set and wires right fired up on 2nd try, still need to adjust points a little better but runs and cuts :)...... next question.. disty has a couple bolts on it does that mean u can adjust this disty like an old car, just loosen the bolt and turn it a little one way or the other to set points better? i`ll wait for u and others to chime in on that going to clean gas tank and sediment bowl tomorrow get it ready im using tempory tank right now till i got it going and thnx to u guys i did thnx

User avatar
Glen
5+ Years
5+ Years
Posts: 5063
Joined: Mon Mar 19, 2012 7:33 pm
Zip Code: 00000
Tractors Owned: 1956 Farmall Cub with Fast Hitch, F-11 plow, Disc, Cultivator, Cub-22 mower
Circle of Safety: Y
Location: Wa.

Re: hey guys need help again so dont laugh:)

Postby Glen » Mon Sep 27, 2021 10:27 pm

Hi,
Good that you got it to run.

The battery Ignition unit is different from the magneto in many ways.

When number 1 cylinder is at TDC, the rotor should be pointing to the upper right, where the number 1 spark plug wire post is. It shouldn't be straight up, that is for the magneto.
You didn't say if the number 1 spark plug wire post is at the upper right on the cap. Sometimes people have changed the wire positions.

Set the points to .020" gap before checking and setting the timing.
Setting the timing doesn't change the point gap, if that is what you wrote above.

Yes, loosen the 2 clamp bolts at the round part of the distributor, and turn the distributor to adjust the timing.
The bolt on the engine side is hard to get to, I use an open end, or box end wrench down behind the distributor, you can only turn the bolt a small part of a turn at a time.
Don't leave both bolts loose when the engine is running.

A 1948 Cub should have 1 timing mark on the front crankshaft pulley. It is the TDC mark.
Using a timing light, align the mark with the pointer when the engine is running at slow idle speed, which should be 500 RPM. Tighten the bolts on the adjustment.

Then you can check and see if the spark advance in the distributor works right.
Hold the timing light on the marks, and slowly speed up the engine, the timing should slowly advance as you speed up the engine, up to about 1/2" above the TDC mark when the engine is at full speed, 1800 RPM for a 1948 Cub. :)

johnnygo
Posts: 11
Joined: Tue Jun 15, 2021 11:25 am
Zip Code: 34428

Re: hey guys need help again so dont laugh:)

Postby johnnygo » Tue Sep 28, 2021 4:16 pm

ok thnx again for this info i`ll try this wknd and let u kno, and yes i was thinking when u turn the disty it would open or close the gap on the points (wasnt thinking of timing) but ok i`ll give it a shot....before i set TDC my number 1 plug wire was at the bottom right of the cap, now after TDC number 1 wire is top right of cap....fires right up :) i`ll try all u said and set the points to .020 right now they r at .013, but so far so good, thnx again and i`ll let u know.


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