Cub starting problems

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Waif
5+ Years
5+ Years
Posts: 1083
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Cub starting problems

Postby Waif » Mon May 17, 2021 9:13 am

zig79 wrote:The cap is not painted. I installed new plug wires today and cleaned out the inside of the cap. Still won't turn over. I had the battery tested and it was good. Cleaned out the jet in the carb and still will not turn over. It tries to but just will not pop.


How much and what strength/color spark you are getting at your properly gapped spark plugs matters.

When you cleaned the towers /pylons inside your cap ...There is a gap between each one and the end of your ignition rotor in turn as it rotates.
(The rotors end/edge needs to be clean too.)
IF we use an abrasive to clean inside the cap , and the end of the rotor (which how else can you "fix" burned or pitted or corroded pylons?);we are speeding up the erosion that happens over time.
Now we have a greater gap for spark to jump. What should that gap be for distance? What happens when we increase that distance?

Your ignition points have a synthetic insulating material they mount on top of. Delicate. When that material is broken , points can ground out. Then no sparky sparky.

Lots of references here about checking for good spark. Not just spark. Good spark. Restart /revisit your no fire symptom there.
Follow that spark from coil to plugs. That is an important part of your ignition circuit . Electricity being created ( or robbed from a battery in your case), stepped up through your coil , and directed by your ...What? Through what? To where?

Waif
5+ Years
5+ Years
Posts: 1083
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Cub starting problems

Postby Waif » Mon May 17, 2021 9:28 am

Patience.
It will start when you get it right.

A couple examples of my non mechanic abilities...

66 Ford Falcon I put the new distributor cap on upside down on. I learned it could be done.
Years later a Ford truck engine tune up on a Sunday evening out in the country.
Each plug wire labeled before removal.
New cap , put wires back as labeled and...No fire!
I had somewhere to be that evening. A long walk to nearest parts place for a firing order book in the distant town would only mean a closed store.
How many possible configurations of plug wires are possible on an eight cylinder? (I learned some). But could see cylinder numbers on cast parts.

I'm not real patient. But am best I can be on tractors.
If I get stuck , I leave it alone a while and ponder.
Today the internet helps. But not as much as...Patience.

zig79
Posts: 12
Joined: Sat Oct 03, 2020 9:37 pm
Zip Code: 63385

Re: Cub starting problems

Postby zig79 » Tue May 18, 2021 6:44 pm

No, not mad at all. I just am not a mechanic, just someone that has two old tractors that I enjoy but can't keep running. So my Cub, when I bought it last year, would start every time provided I would disconnect the negative battery cable. That's what the owner told me to do. I forgot once so I need to charge the battery. I added new battery cables last year thinking that would help but I would still have to charge the battery after every use. This year, after sitting in the bard all winter I charged the battery and it started right up. Then after a day it would not start. I added fresh gas, charged the battery and nothing. I ordered a hand crank, turned it one time and it started right up, next day started it again with the hand crank. Since then it will not start. So when I use the starter it tries to start but won't fire. Also when I attempt to use the starter three or four tries it drains the battery. The hand crank will not get anything to pop.

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Rick Spivey
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Posts: 2685
Joined: Sun Jul 01, 2007 10:07 pm
Zip Code: 29518
Circle of Safety: Y
Location: SC, Cades 29518

Re: Cub starting problems

Postby Rick Spivey » Tue May 18, 2021 8:15 pm

So if you are having to disconnect the battery, then that indicates a drain somewhere. I will assume that you would have noticed if the lights were still on, so I'll rule that one out. So I'm betting the coil is remaining switched on. That would indicate either a bad switch, or some issue with the wiring. I suggest you get the appropriate wiring diagram off here, and see if the wiring is at least correctly routed. If yes. then likely you have a bad switch. Once the battery is run down low enough, the tractor will no longer run, as it needs the battery voltage to fire the spark plugs.
Rick Spivey
'52 Cub ("Great Personality") 148xxx
'48 Cub with FH ("Gunny Cub") 38xxx
'57 Lambretta (a slow work in progress)
'74 Triumph TR6 (Mama's toy)

Waif
5+ Years
5+ Years
Posts: 1083
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Cub starting problems

Postby Waif » Tue May 18, 2021 8:25 pm

To compare. (?)

My first Cub , the battery acted wonky. Was not the battery , but the connections. Importantly , it was my ground on the opposite end away from the battery.
Even had a friend tow me home with a John Deere once. (Oh the shame!) Yes , I acquired a hand crank after that.

Went to a braided ground cable and all was well. Often undersized cables get used by previous owners by grabbing a common 12 volt type cable.. But contact points of cables matter highly too. Both were problems I'd had.

With a charged battery , if it don't crank well , (or not at all as happened to me multiple times) it's not the battery as likely as connections and size of cables.
Charging (by the tractors system) is a separate issue.
This all assumes you're running a 6volt system. ( 6volt wants a generous pathway to run/flow through. Bigger cables than 12 volt..)

Mind Rick's mention of a potential parasitic draw.


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