Wallfish

The 20A engine is bigger than the Compact engines are but I'm not sure if the size of the fogger part itself is different. 

Very Nice Find ! Not very many of those pop up for sale
I have one with a 20A engine but not one of those smaller ones.

It's a check valve. Make sure you can blow through it in one direction (Flow direction). It may be clogged up from old 2 stroke oil.
If it's clogged you can leave it off

That thing looks to be a great condition.
The diaphragm in the carb will need to be changed. When they get stiff it won't prime or pump fuel. And clean the carb. You can follow the pinned carb tutorial. Shoot me a PM for a diaphragm.
Check for spark. If no spark you will need to remove the flywheel then the points cover to clean the contacts on the points.
Obviously clean the tank too
Yes that's the engine shut down

Also, just picked up this “Ranger”.
I can’t find much info on this one. Any ideas on the manufacturer?

Here’s a couple of pics from when I got it.  In a few pieces now. Getting things cleaned up. 

That thing looks to be a great condition.
The diaphragm in the carb will need to be changed. When they get stiff it won't prime or pump fuel. And clean the carb. You can follow the pinned carb tutorial. Shoot me a PM for a diaphragm.
Check for spark. If no spark you will need to remove the flywheel then the points cover to clean the contacts on the points.
Obviously clean the tank too
Yes that's the engine shut down

That information kinda mirrors the O&R engines
Screw from the back early engines
Screw on from the front middle year engines
Then the screw on starters about 1970

It was media blasted. Im not sure with what exactly - and It's a TAS P-7
Here's my resto-mod today. You can scroll up above to my April 2018 post and see the before picture. The chain guard mold will be made this summer 2019 - then copies. I will later in the year make the seat mold and copies 

I must be a lucky guy, cause I've still got mine!!! And, just recently discovered it's history, and Rarity!! Resto has already started.

Not that large one pictured. The smaller discs should be attached to the diaphragms. I use a product called "Seal-All" because it stands up to gas.

I bought this for $20 in a bin on market place completely disassembled. 
So far I have been able to put it back together for the most part. I have realized I am missing the angled airfilter, the 2 shields that go around the cylinder head and the correct chain. I was able to source the right chrome handle off ebay. I was also able to re bend the recoil ends to there original shape off some pictures I found on here.

Maybe it's ground a negative wire to the case and the positive post ???  2 posts are 12v. 
Do you have a multi meter if it's not in the manual how to achieve the 6v? I breezed through it but didn't see anything.
Wish @factory David was still active. He always seemed to have the answers for stuff like this.

Thumb and fingers. 

Hold the spring down with your thumb at the holder opening and pic out the holder with something sharp. Release the thumb pressure slowly so the spring unwinds slowly 

Yes. Anything to hold the rope as long as it gets locked on the spool

The wire needs to be bent in such a way to feed both ends of the wire through the holes from inside of the spool out. The factory pieces resemble 1/2 a paper clip and the wire is kind of soft

With a little bit of fuel in the tank, connect a piece of fuel line to the nipple and blow into it. The one that bubbles the fuel is carb line.

The shape of tank. The line from one side to the other allows air to escape out the top. Otherwise the opposite side from the fill neck would just remain an air bubble on the top without it.  So that line allows it to fill all the space so the tank holds more fuel

You can get the 2 sections off without removing that hole plug cover

I guess now I need to try to find one of these with an O&R for my wifes collection.

Courtesy of 10242130
 
Here is a Brochure picture of a Little Petro minibike.It was made in the early to mid 60's by Odom Manufacturing.This is the same company that made the Petro Powered Products Drill that is on this site along with quite a few other Ohllson & Rice powered tools.Jim Odom also Produced the Comet C Saw for Comet.I will be putting pictures of my Little Petro bikes on this site soon,I need to crop them all as the file size's are too big . Only about 12 of these bikes have been located to date,quite a rare bike.
 
This particular Brochure shows the bike with a TAS engine,but early on,they used the Olhsson & Rice.

With O&R

I think she is up to 21 or 22 now. 

I never checked if the dc was working. When I put the 2 probles of the meter in the plug socket and put it on continuity it beeped indication of a short.