Jflair

This is super cool!  Great job!

It’s not mine just thought you guys may want to check it out!:)

Hi Richard,
 
Thanks for that link, 1966 & 1HP makes more sense, the earliest O&R parts list I have mentioning the compact III (1HP) is dated November 1965, that doesn't imply that they didn't introduce it earlier that year of course.
The information in the link seems mostly fine, I will see if I can find any more reference to the 16:1 ratio in any of my original O&R literature, I just checked a few yesterday.
One thing I don't agree on in the link is the last comment " Used O & R model airplane engine " I think it should really say something like 'used O&R compact industrial engine' as the O&R Compact was developed as an industrial engine (although model makers did & still do use them for other things), here is something I found from an archive document relating to that;
 

 
I remembered recently buying a parts list dated Apr 1964, hopefully this scan from it helps better with the (early) original ratios, I will edit the calculated 10.67:1 ratio to 11:1 in yesterday's post. Of course modern oils allow higher ratio to be used, as has already been said;
 

 
David

That is a very nice condition later Tiny Tiger with the larger gas/fuel tank.
I will check the manual for mine, but I wouldn't recommend using a 350W load continuously, something like a 250W maximum load for continuous use would be better to avoid damage (which is what the early ones were rated for).
Those starters can be tricky to repair till you get used to fixing them.
 
David

Here is the little tiger I believe it’s a later mode type 219 350w shroud says compact 3 bought a few new diaphragms from a member on here carb thread was Awsome had to do all of it and went off without a hitch! String thing was a bit tricky but a few tries got it done;) once I get this oil thing figured I’ll start it and make a video!:) I ordered some synthetic and some 30wt I’ll try them both and see thanks again love the input!

Here is the little tiger I believe it’s a later mode type 219 350w shroud says compact 3 bought a few new diaphragms from a member on here carb thread was Awsome had to do all of it and went off without a hitch! String thing was a bit tricky but a few tries got it done;) once I get this oil thing figured I’ll start it and make a video!:) I ordered some synthetic and some 30wt I’ll try them both and see thanks again love the input!

I'm not sure where you found that information but there were no 1HP O&R engines in the early 1960's (only 3/4HP) and the only mention of a 16:1 ratio is for the much later 1970's 1.6HP Model 20A engine, there seems to be a lot of incorrect information around for these engines.
 
Here are some old fuel/oil mix ratios from the various O&R manuals & literature I have, the ratio changed over the years;
1961 & 1962: 3/4 pint #30 SAE oil per gallon (11:1 ratio), these early compact engines where rated at 3/4HP.
1963: 1/3 pint #30 SAE heavy duty oil per gallon (24:1 ratio), again only 3/4HP compact engines available then.
1966: 1/3 pint #30 SAE heavy duty oil per gallon (24:1 ratio), for all 3/4HP, 0.85HP, 1HP compact engines.
 
From the NIAE test report (published 1964), "the petrol/oil mixture has been changed to 24 parts petrol to 1 part oil and the recommended grade of oil is heavy duty M.S. type SAE 30" (was 3/4 pint to 1 gallon when they did the testing in Jan-May 1963) many design changes were made following this report.
 
There was also a mention of chrome cylinder linings, here is the information I have for some of the O&R engines;
1963: Early compact engines had a steel sleeve cylinder with chrome piston rings (earlier information from 1960 doesn't mention the rings being chromed)
1975: Model 13B engine (1HP) has steel cylinder liner with special alloy cast iron rings, and to confuse things more the brochure (undated) for the newer Model 20A engine (1.6HP) gives a 16:1 fuel/oil ratio using either SAE 30AD or MS motor oil, these engines had a chromed cylinder bore.
 
Forum recommendation for fuel/oil mix ratio;
We have been recommending a 32:1 fuel/oil mix on the forum for using modern 2-stroke oils, I have been using a high quality mineral based 2-stroke oil from Stihl, another forum user had problems with the synthetic version of 2-stroke oil from Stihl, see this thread;
 
Obviously you may need to experiment to find something suitable that is available where you are, but I do not recommend oils sold by petrol stations for use with scooters (tried some of that in a Villiers engine many years ago, it was far to smoky), the best stores to try and find something suitable would be a local store that sells & repair garden or ground maintenance equipment, chainsaws etc.
 
Note the all the O&R compact engines & the newer Model 20A have seals made from rubber and also on earlier production engines they used plastic cages for the bearings, these can be damaged by certain additives in some types of fuel/oil.
 
Also if you intend to store the engine for any long period it's recommended to drain all fuel and to put some oil down the spark-plug hole, pull the starter a few times to coat the cylinder & piston and leaving the piston blocking the exhaust ports.
 
I must admit I don’t know if the fuel sold in the UK has ethanol in it, I guess that is something else to look out for which may or may not have harmful additives.
 
David
 
 

I forgot to add that you should check out the carb repair thread if you haven't already and it's a good idea to clean out any old crumbly filter foam from the air filter housing, it can damage the engine if any of it gets sucked in.
 
David

I've always been an advocate of "old oils for old engines" - most of which in the UK are Villiers with plain bush main bearings and no oil seals. The extra "body" of straight 30 grade does appear to be beneficial in sealing the mains. Not sure where the OP was posting from but in the UK there is no problem in obtaining straight SAE 30 or 40. 30 is often sold as Lawnmower oil, locally Tesco, B&Q and Halfords have it. it's also sold as Classic Car Oil. Millers and Morris lubricants both sell a "classic bike mixing oil".
 
On a slightly different track, the manufacturers of Aspen alkylate fuel have been promoting it as having less carcinogenic properties together with resistance to the worst effects of ethanol and reduced shelf life. Then, a couple of weeks ago, the UK distributor of Cobra chainsaws issued a service bulletin that on no account was an alkylate fuel to be used in one Cobra model as it had been found to cause piston and bore failures.  

Hi, I'm no expert with these engines, but I checked the records for an O & R 1 Hp Chainsaw model from early 1960s and it lists ratio as 16-1.
Now I have had discussions with the Chainsaw Website owner in the past and he reckons that if you have an engine that has a Chromed bore, then that Petrol/Gas ratio can be increased safely to 25-1.
My 72 Beaird-Poulan Chainsaw has a Chromed Bore and I use that ratio, as well as classic 40wt Mineral Oil (to avoid any issues with synthetic additives affecting the old Oil Seals).
I also find that 25-1 is mentioned for these O & R engines on U-tube examples.
As for a suitable Oil available in your Country, I found this example is basic Mineral with no Additives-  OIL
API-SA  grade is devoid of Additives listed here-
    
 
I'm sure there will be a fellow expert Countryman along  at some stage to offer guidance, as I'm on the other side of the Pond. 
Hope this helps

Richard is right on track.
I can give you two of the most often followed thoughts. First all people agree modern 2 stroke oils are much better than the old 30 weight motor oils used in mixing in the past. Old school people will most often use a top quality synthetic or synthetic blend 2 stroke oil like a Stihl or Lucas oil at a mixture of 25:1 to 32:1 on equipment previously spec'd for 16:1. Newer old machines that were spec'd at 32:1 are often run at 40:1 to 50:1 with modern top quality synthetic oils. There is a danger of using both too much oil or not enough oil in case you were unaware. Too much oil can cause a carbon build up that could seize a piston or score a cylinder, probably not as bad as not enough oil, but it does happen.
 
If I were going to use the Tiger on a limited basis I would lean to a little bit more oil (25:1), and if I were going to use it more often I would use the 32:1 ratio. I use nothing but Amsoil Saber Professional  2 stroke oil and in my new Husqvarna 525LS that is spec'd for 50:1 Amsoil can be safely run at 100:1 ratio, but I will only go as high as 80:1, because I feel better with a little more oil. I will say Amsoil Saber is the finest two stroke oil in the world and because you can mix at a higher ratio it is more economical. On Amazon or eBay a quart will run about 20.00 delivered to your door, I doubt you will find it for sale locally, but hey you might.
 
The New School people are often using 50:1 Amsoil or Stihl 2 stroke oil in old machines that were spec'd for 16:1 and 32:1 that claim no ill effects or damage and they are using this equipment on a regular basis and even under fairly rugged conditions, but personally I'll stay with the first tack.
 
As for fuels, I would only use non ethanol fuel. If you cannot obtain non ethanol fuel I would use True Fuel premix at 32:1