Another 300 electrical question

[300guy]

Should my 300 (6 volt) have a bypass circuit from the starter to the coil? It never has had one as the wiring is original but sure acted like that. The past 6 months it has developed a hard starting problem for some reason. Yesterday I choked it, which I never have had to do in the past, and it would not pop, snort or anything until I accidentally let up on the key instead of shutting it off and it started and ran right away. I have had for over 10 years a Pertronix and it has always started within two or three revolutions. Would a weak battery do this even though it cranks over real good? My battery is quit old also? I did not have time or a long enough jumper wire to run from the battery to the coil to test to see if it would run when cranking this way. Coil had fire, 1/4 inch and a yellow color and when I checked a plug wire, all I had at the time was a 1/4 inch bolt I stuck in the plug wire and it never jumped a gap but it would kinda shock me. So I am now trying to figure out is it the coil or a voltage drop somewhere in the wiring to the coil, or a weak battery if that is possible. The tractor is 2 hours away so it is not just walking out the back door to do some testing.

 

[old]

There is no ballast resister on a 6 volt system so in turn no bypass circuit. You probably have a spark problem as in the points need to be cleaned and regapped or a carb problem

 

[300guy]

I have prtronix

 

[old]

Electronic ignition go bad over time so you need to make sure you have a good blue/white spark that jumps a 1/4 inch gap or more

 

[300guy]

It is working fine. Runs great just has started doing the fickle starting problem.

 

[old]

Weak spark at starting can cause that as can a starter that is going bad and pulling to many amps or a carb problem. One has to trouble shoot problems like that

 

[Jim.ME]

(quoted from post at 15:55:29 04/22/22) It is working fine. Runs great just has started doing the fickle starting problem.

Check the voltage at the battery and at the starter when cranking. Also checkvoltage at the coil input terminal when cranking. A weak battery or worn starter could be causing a drop in voltage to the coil. When did you last clean both ends and connection points of both battery cables?

 

[used red MN]

I would echo everything in JimMEs last two sentences.
In particular a heavier amp draw from a wearing starter
will reduce cranking voltage.

 

[Brownie450]

You need to check voltage on the battery posts---not
the clamps on the posts while cranking. See if the
voltage drops much less than 6 on the battery posts.
If that checks out, move the test leads to the clamps
on the battery cables. Read voltage while cranking &
see if voltage holds around 6 or a little less.
I'm betting the battery is showing its age &/ or has
a bad cell.
Jim

 

[old]

He said the same things I did but he was just a minute or so behind me as for his post posting

 

[Janicholson]

This tester is cheap and reads accurately enough to assess the amp draw of the starter. Less than 200 to 250 is OK, more than that is an indication of a starter needing rebuilt. Jim
one source.

 

[300guy]

I looked back through my maintenance records and I installed a new battery in January of 2014. So That was my first thought when this started going on, but yet it still cranks really good. It shows no sign of drag or anything like that. It was an NAPA battery with 900 CCA.

 

[Brownie450]

Thinking back, we had a '66 Ford truck that did
that same thing===would not start but would crank
like crazy until you stopped cranking & then it
would start when letting the key go back to run.

This was with a brand new battery.
Finally replaced the battery & no more trouble.
Jim

 

[Jim.ME]

Sometimes you need to do the basic checks, even if something seems ok, to find a problem. Good luck.

 

[Janicholson]

Something not mentioned is a bad or failing ignition switch. If it or wire connections are getting bad it will pass enough to start only when releasing the key. Do an old based check by wiring from the battery to the coil direct (hot wire) if it fires easily it has supply side issues with ignition circuit. Jim