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bursitis
04-14-2019, 05:28 PM
been tinkering with the 6U D4 all day. when i first bought it there was a 12 volt battery on it. since then i have restored the charging system and returned to a 6 volt battery. the pony started just fine on the six volt and life was good. but now the darn thing will start with the rope second pull but it wont start with the electric starter. it seems to be spinning fast enough or at least not any slower than it used to and the battery is the correct size. what do you think??? mag impulse???

Oldcarman
04-14-2019, 05:45 PM
Sounds like weak spark. As an experiment, reduce your spark plug gap down to about .015" or so and see if it starts with electric starter. I'd guess that the spec is probably closer to .020" plug gap but you don't want to run much wider than that with a magneto. Resistor plugs, resistor wires and connections on the secondary side can all come into play with hard starting. If your plugs are dirty, put them in a pan and cook them on your stove in vinegar for a while. It works great.

Could be corroded points, bad condenser, partially failed magneto coil or weak magnets. When you are rope starting, you are probably turning it over TDC faster than your starter giving the mag just enough to fire off the cylinders.

bursitis
04-14-2019, 05:52 PM
yea i need to pull the plugs. probably new wires plugs etc would be good. please explain cooking the plugs in vinegar? do i immerse the whole plug in the solution or just the tip? do i boil the vinegar or just get it hot?

STEPHEN
04-14-2019, 06:26 PM
There is no impulse on that magneto, and what, you say vinegar? I will have to try that one day

Oldcarman
04-14-2019, 09:29 PM
There are probably lots of ways to clean plugs. I remember cleaning plugs when I was young by boiling them in vinegar for about 30 minutes. I haven't done it in years, but I remember it working pretty well.

Remember when repair shops had those spark plug cleaners that would sandblast the plugs? Eeek!

Neil
04-14-2019, 09:45 PM
Use solid core plug wires. I got a set of wires from Brillman as I could order them on the net and they came with boots, tips, etc. $20 I think?

d2gary
04-14-2019, 10:16 PM
I hate the smell of vinegar and for a couple bucks a piece just buy some new ones

dpendzic
04-15-2019, 08:27 AM
There are probably lots of ways to clean plugs. I remember cleaning plugs when I was young by boiling them in vinegar for about 30 minutes. I haven't done it in years, but I remember it working pretty well.

Remember when repair shops had those spark plug cleaners that would sandblast the plugs? Eeek!

That was one of my jobs in my fathers shop--cleaning and regapping plugs. we had this big old spark plug cleaner, and also had a pressurized spark plug tester.
you can still by spark plug blasters--Hf has one for $15

this was when i was around 8 years old, my other jobs were pumping gas, grease jobs and oil changes, spraying suspensions with penetrating oil, tube hot patches and riveting brake linings

bursitis
04-15-2019, 06:50 PM
put a set of NGK AB-6 plugs in the pony today. she starts on the second rotation now. i messed up one of the plug wires though. i jurry rigged it for now but i need a new set of wires. suggestions???

dpendzic
04-15-2019, 07:57 PM
I ordered the same ones Neil suggested

https://brillman.com/product/caterpillar-d2-d4-late-with-pony-motor-2-cylinder-spark-plug-wire-set/

bursitis
04-15-2019, 09:19 PM
yes those look real good,i think i will get some. i am a little confused as do i need the early set or the late set? my tractor is a 1953 year. i think the late set might be for the Buzz Bomb used on the D4C???

drujinin
04-16-2019, 06:30 AM
Your local NAPA has solid core wire on a roll and all the other associated parts

bursitis
04-16-2019, 07:27 AM
Your local NAPA has solid core wire on a roll and all the other associated parts

i live in a pretty rural area. i went to town yesterday to get some wire and the appropriate ends to make a set of wires and couldn't buy anything but a pre packaged set for modern cars.

dpendzic
04-16-2019, 07:30 AM
I bought the later set for my 55 D4--i think its just the length and the later pony engines have the spark plug in the middle of the head instead of at the top

bursitis
04-16-2019, 07:59 AM
I bought the later set for my 55 D4--i think its just the length and the later pony engines have the spark plug in the middle of the head instead of at the top

Thanks. i didn't know the spark plugs changed locations. both of my D4's pony engines have the plugs in the top of the head.

old-iron-habit
04-16-2019, 09:11 PM
i live in a pretty rural area. i went to town yesterday to get some wire and the appropriate ends to make a set of wires and couldn't buy anything but a pre packaged set for modern cars.

As stated make sure they are solid wire and not the resistor type. Been a number of years since cars had solid wire plug wires.

bursitis
04-16-2019, 09:20 PM
As stated make sure they are solid wire and not the resistor type. Been a number of years since cars had solid wire plug wires.

Thanks You.