John Deere B won’t start

[HoosierMuscle]

Hello. I got this tractor from a barn with no knowledge of status when parked.

1948 based on serial 223026.

I have cleaned the carb, tank, and fuel bowl. Ive put a new 6V battery on it. I put a new starter switch on it. Plugs and points have been gapped. Condensor tests good. When I try to start it, it doesn’t turn over very fast. When I pull both plugs to check for spark, I have spark and the engine turns over much faster.

Thoughts, ideas, suggestions?

 

[38 Sears Roebuck]

Did you open the decompression petcocks? One on each side (cylinder).

 

[HoosierMuscle]

Did you open the decompression petcocks? One on each side (cylinder).

Wasn’t even aware of those? So open those to start and then close after running? That’s what I just tried and she fired up!

 

[Fixingfarmer]

yes that’s exactly what to do the later ones had this as the compression increased. I wish my early b had it with the hand start.

 

[HoosierMuscle]

Thanks all. This is the oldest tractor I’ve worked on yet so learning some new things!

 

[38 Sears Roebuck]

Glad to help. I owned a 1952 B at one time and grew up around those "Johnny Poppers". Have fun and be safe especially with that front end loader. I had a friend tip one over and it killed him.

 

[Mike(NEOhio)]

Looks like you got a good one. They never turn over very fast, even the later 12 volt systems. You shouldn't need to open the reliefs at normal temps. I only use them on my 51 A in the coldest weather. I don't know when the Bs went to 12 volts, Is there room for two 6v batteries in the box?

 

[620 John]

B's were all 6 bolt as far as I know. With a 6 bolt they turn pretty slow. Put a 12 volt in and then they turn plenty fast. With that being said if everything is working the way it's supposed to it shouldn't need to have the petcocks open for starting unless it's really cold out and/or battery is weak. Or it's possible your B has high compression pistons in it.

First thing I'd do is perform a voltage drop test with a multimeter across the battery cable going to the starter and across the ground side of the battery to the starter case. To do a drop test you touch one lead to one end of the cable and the other lead to the other end of the same cable. Then hit the starter and read the volts on the multimeter. Should read less than 1 volt if the cable is good.

If the cables and ground connection is good then you need to test the starter which requires an amp meter. If you don't have an amp meter take the starter to a rebuild shop to have it tested.