R Pony Motor Starter Update

NoDakInMN

Member
A while back, I posted looking for information on how to determine if the R I was working on had been switched to 12 volt from 6 volt. To quickly recap, the starter was not rolling over the pony motor hardly at all and when I took it out and used a battery charger to power it, it only worked on 12V negative ground.

Well, it turns out the starter was indeed 6v volt positive ground. I was trying to figure out if my issue was the starter, the cables or the battery, and the battery charger hooked up to the starter led me down a blind alley.

I was not able to get back to for a while, but at the end of this week I had some time again. I was pretty sure the battery was OK as I had taken it out of my other R where it always started the pony without missing a beat. I had toyed with the idea of getting a new starter or cables, but the technician in me refuses to be a parts changer, so I needed to figure out a way to troubleshoot this.

So what I did was get a set of 4 gauge booster cables and cut the clamps off of one end. I then took a large set of electrical grounding lugs, a component where there is a flat bar, with a hole in it so you can bolt it down, but is attached to a clamp that will accept a cable, and I put those on the ends of the booster cables. I then bolted one end to the frame of the pony motor and the other on to the starter lug and then put the clamps on the other end on the bare battery terminals. This allowed me to bypass the lead to the starter but also bypassed any potential loss of ground created by the seat bracket or anywhere else in the path. This also allowed me to put a volt meter on the lugs so I could monitor the voltage while operating the starter at the pony motor. I had 6.3 volts, but when I activated the starter, voltage dropped to zero. I had another 6 volt battery, so I brought it over and hooked up to that and the starter spun the pony over like it was supposed to. I then hooked up the battery to the cables on the tractor one at time to check them out and they were OK. So I went and got a new battery and that problem was solved.

So instead of spending money on parts that were OK, I spent $25 to make a diagnostic tool out of booster cables. I am gong to keep them that way, because I will probably need to use them in this manner again.
 
Great diagnosis job and thank you for sharing your solution to the problem!

It's funny that the battery cranked the other R well, and not this one.

Glad you're up and running!
Brandon
 

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