Resurrecting a Model B 12V system

Hi. I have started to bring a 1947 Model B back to life that has been sitting under the shed. It ran back in 2005 or so and was then parked under cover and has sat ever since. No one knows what has been changed over the past 70 some years on the tractor, so I'm trying to figure that out before I harm anything.



This post was edited by briant on 08/05/2022 at 07:34 pm.

It didn't have a battery in it, so I'm trying to determine if it was 6V or 12V. The recollection of the older people was 6V, but it has 12V light bulbs and appears to have an alternator.

img]https://forums.yesterdaystractors.com/photos/mvphoto95546.jpg[/img]

Does anyone have advice to determine if it is positive or negative ground for the battery?

There is an ignition. Based on the picture below, does anyone know if it may be a Magneto or Distributor?



I have started by cleaning out the fuel system. I had never seen fuel varnish like this before. But a little M.E.K. brought it back to life.






I'll appreciate your thoughts on how to figure this out. Overall, this system looks fairly simple. The only other issue is it's missing a key. So, I'll need to figure that out once I can get a battery installed correctly.

Thanks,
Brian

This post was edited by briant on 08/05/2022 at 07:35 pm.

Magneto ignition. Not sure but I'd guess it's 12v positive ground for the starter and lighting. Should say 6 or 12 on the generator plate.

Hi, Mike.

I didn't see any markings on the generator/alternator. But, it looks like a standard car part.




This post was edited by briant on 08/06/2022 at 05:25 am.

Thats an ALTERNATOR most likely 12 Volt (use a 12 volt battery) and most likely NEGATIVE Ground. I can't
say for sure how its all wired up ?? Perhaps its a ONE WIRE setup ?? which ONLY requires a wire off that big
main rear output stud up to the LOAD (NOT Battery/Starter) side of the ammeter...

The Ignition is a Wico X Magneto so it doesn't use or care about battery voltage or polarity

John T

Look at the battery cables ends in the battery box. One of them should have a smaller opening than the other
one. If the cable with the smaller opening is connected to the battery box or somewhere on the tractor frame
it is a Negative ground set-up. If the cable with the smaller opening is connected to the starter it is a
Positive ground set-up.

Common Delco 10SI 12 volt likely negative ground alternator. Black plug on edge indicates it is a one wire configuration.

Lights and starter don't care whether positive or negative ground, mag is a circuit unto itself and doesn't care about battery ground polarity since it is not connected to battery power.

Only other device that will be polarity sensitive will be the ammeter. Lights on, engine not running it should indicate negative. If not reverse connections.

[b:654c4848f0][i:654c4848f0]The only other issue is it's missing a key[/i:654c4848f0][/b:654c4848f0]

Take a look at the [b:654c4848f0]DISTRIBUTOR (WICO) AND IGNITION LOCK[/b:654c4848f0] diagram below.



Note the Yale Key (Key 46).

Also note [b:654c4848f0](Tractor Serial No. B268820)[/b:654c4848f0].

The key was installed on distributors during mid-1950s.

If necessary, a [i:654c4848f0]universal[/i:654c4848f0] lock and key can be installed.





Hope this helps.

Thank you all for your input. Good progress made today:

- Battery installed: battery cable clamps were different sizes. It appears to be a neg ground.

- Ammeter reads charging when I turn the headlights on. They may not have fixed the gauge. More investigation needed on this one.

- The fuel is drained from the tank and carburetor. So, I tried the starter and the engine turns over just fine. That's very promising.

https://youtu.be/jdHgL5gA4Gg

The engine appears to be turning in the correct direction based on the fins on the cooling fan. If the battery was reversed, would the starter turn the engine backwards?

On to the key/magneto function. I looked more closely at the back of the key switch. There is only one wire connected to it. I think the only purpose of the switch is to ground the magneto to stop ignition. If that is the case, I think I can just disconnect it for now and touch it to the engine block to kill the engine. Is my assumption correct?

Thanks,

Brian

This post was edited by briant on 08/06/2022 at 02:33 pm.

Hi again Briant, thanks for the updates, heres my response:


- Battery installed: battery cable clamps were different sizes. It appears to be a neg ground.

Probably right, most all Alternators (unless special built) are indeed NEG ground so be sure to connect
the battery that way.......


- Ammeter reads charging when I turn the headlights on.

If when not running a load makes the ammeter swing to + Charge (should be - discharge) and since it was
originally POS Ground, the leads likely need swapped. NEXT test is to see if when running its charging ??
If charging battery voltage when running at fast RPM should rise to at least 13 up to 14 or so subject to
RPM, alternator and battery. Similar you have to have the ammeter wired correct so it swings + Charge (if
alternator is working) but - Discharge as loads are applied


The engine appears to be turning in the correct direction based on the fins on the cooling fan. If the
battery was reversed, would the starter turn the engine backwards?

NOOOOOOOOOOOO it will still turn the same regardless of battery polarity

On to the key/magneto function. I looked more closely at the back of the key switch. There is only one
wire connected to it. I think the only purpose of the switch is to ground the magneto to stop ignition. If
that is the case, I think I can just disconnect it for now and touch it to the engine block to kill the
engine. Is my assumption correct?

Typically a Mag can have a simple one wire KILL SWITCH that kills the spark if connected to ground which
can be the frame YES assumption correct

Youre doing good, you got this

John T

You didn't say it had an alternator. Should have included the picture in the original post.

Thanks, John.

Your thoughts are much appreciated. I'll keep going at this tomorrow.

Brian.

Hi, Mike.

I'm struggling with the pictures in these posts. When I try to include them in the initial post it won't let me post as it thinks I'm violating the community guidelines. I'm having to edit my posts after posting to bring the photos in-line. I missed that photo the first time.

Thank you for your thoughts and comments!

Brian

''On to the key/magneto function. I looked more closely at the back of the key switch. There is only one
wire connected to it. I think the only purpose of the switch is to ground the magneto to stop ignition. If
that is the case, I think I can just disconnect it for now and touch it to the engine block to kill the
engine. Is my assumption correct? ''

If your B has only one fuel tank it is a straight gas tractor. To shut down the engine on a straight gas,
magnito equipped tractor all you have to do is pull the throttle lever alway the way back. A key switch is
only used on a battery ignition/distributor equipped tractor. Disconnect both ends of the ignition switch
wire and throw it away.

(quoted from post at 19:46:17 08/06/22)
Hi, Mike.

I'm struggling with the pictures in these posts. When I try to include them in the initial post it won't let me post as it thinks I'm violating the community guidelines. I'm having to edit my posts after posting to bring the photos in-line. I missed that photo the first time.

Thank you for your thoughts and comments!

Brian

Click to expand...

Normally you need 5 posts before the site will let you upload pictures. You're over that now, so I would think they should work for you now.

You're welcome. Back to the KILL SWITCH I was a used tractor dealer and farmer back in the day and saw
allllllllllll kinds or magneto kill switch arrangements. Some were a Toggle Switch,,,,,,,,,Some were an
On/Off Push Switch,,,,,,,,,,,Some were a Key operated On/Off Switch,,,,,,,,,,They still worked the same
and I saw plenty of them on BOTH battery started tractors as well as hand crankers

REGARDLESS (hand cranker or battery start) the kill switch stud/wire if connected to frame/ground killed
the spark

NOTE Many Mags DID NOTTTTTTTTTTT have any kill switch at all. On those you pulled the throttle back to
stop the engine

John T

I removed the one wire from the key (it traces back to the side of the Mag case) and if I touch it to the chassis when cranking it does spark, so it looks like they were using the key to ground the mag.

I tried to start it today with fuel in the system. No luck. When I took the spark plug out of the hole and cranked it over, it throws fuel out the spark hole. I waited 2 hours and cranked it over again to the same effect. Looks like I need to take the carb apart and see what's stuck or gummed up causing a way too rich scenario. I'm guessing the float / needle is probably stuck. I'll find out more when I tear into it. I'll wait to do so until a carb rebuild kit arrives.

Brian.

When you tried to start it did you advance the throttle lever a little bit from the ''all the way back
position''?

If not, advance the throttle lever and try again to start it before you tear into the float/needle.

I was in your exact position 3 months ago with a 49 B.

I got rid of my ignition switch because the throttle can shut it down and there are no theft or kid safety issues.

Mine is very touchy at start up too. The PO came over at the beginning and told me to just crack the throttle, roll it over till it catches and then goose it a bit. They flood easy. You have to find the sweet spot for starting.

This post was edited by ajhbike on 08/09/2022 at 01:07 am.

Since you mentioned that it was spitting out fuel and the float might be stuck, you might want to check and make sure the crankcase isn t full of gas since it has been sitting for so long