Re: 100:1 Mix
Let me beat this dead horse a couple times!
Let me open by stating that change is one thing that is very hard for us humans. Running 100:1 Opti-2 in our Happy time/China Girl engines is going to be hard for some people. To me, I tired it to prove that it was O.K. I've had the engine since 2004 and wouldn't be out too much if the engine seized. Heck, how much does a new engine cost?
I've been using Opti2 in all my 2 stroke engines, even the cheap 2 stroke generator that I bought for under $100.00. Smoke and residual oil are less than before. Look on the Internet and see how many landscape gardening, tree trimming, etc. persons have reported using 100:1 Opti-2 for years without any problems.
In my small town, the local ACE Hardware sells a lot of Opti2 to persons who use it everyday at a 100:1 ratio. If it damaged their engines, don't you think it wouldn't sell? They're the ones who use it to support their livelihood.
My guess is that the Happy Time/China Girl gas to oil ratio was developed years ago by the Russians who probably used regular 4 stroke crankcase oil with no additives. It just wasn't available at the time or place. Use more oil and your less likely to have engine problems.
The Chinese copied the Russian design and probably copied the same oil to fuel ratio. If it works why change it. Another possibility of staying with a 16:1 ratio maybe due to the lack of quality oil used by Chinese consumer or most individuals could only afford the cheapest oil that lacked additives for engine protection. The last possibility is to reduce the number of returned engines. If you required people to run the engines with a high oil to fuel mixture, more than likely, they won't have engine problems, other than a fouled plug every once in a while. It is cheaper just to tell the customer to clean the spark plug every one in awhile than having seized engines being returned, especially with a low profit margin.
Import dealers probably stayed with the same oil to fuel ratio as the Chinese. Again, if it works, why change it. Like the Chinese, importers and dealers are less likely going to have a warranty problem and higher consumer satisfaction with a higher oil to fuel ratio. In addition, importers and dealers have a very low profit margin. Of course, over time, spark plugs will foul, head will form carbon deposits and exhaust pipes will get plugged - So what, most of us don't complain about those issues after several thousand miles. We've got our money's worth.
My AMF Roadmaster McCullough engine built in 1978 required 40:1 BIA (Boating Industry Association) certified oil, but in an emergency could use regular 4 stroke oil at a 16:1 ratio. This is listed in the Owner's Manual. The Manual then states: : "At the 16 to 1 ratio, spark plug fouling could occur."
BIA has been superseded by the National Marine Manufactures Association (NMMA). TC-W3 is the current two stroke oil certification program. Do you think the oil certified by BIA in 1978 is the same quality as the TC-w3 oil certified by NMMA? I don't think so.
Here's a quote from NMMA regarding the TC-W3 Certification: " The long term objectives of the two-stroke engine industry have been to reduce emissions which contain burned and unburned oil that have passed through the engine, and to develop a quality of oil that reduces the mixture ratio to fuel while extending the life of the engine. That means significantly reduced emissions to satisfy EPA requirements, less warranty problems, and increased customer satisfaction due to engines lasting longer with less maintenance and overhauls." Seems similar to the Chinese and American importers and dealers - less warranty problems and increased consumer satisfaction.
Interesting how the TC-W3 Certification process works. Oil manufacturer/marketer submits oil for testing, NMMA tests it on engines in a laboratory and then certified to be used on two stroke engines. Is it the oil companies via NMMA and other oil certification associations that set the oil to fuel ratio or the engine manufactures setting their oil to fuel ratio based on results from NMMA and other oil certification associations? According to NMMA, they test at different oil to fuel ratios, as part of the certification process.
All I know is that Opti-2 works and I haven't burnt up my engine - even running it over 25 miles in 100+ degree temperature. I am sure some one on this forum would have complained by now. As long as your fuel/air mixture is correct, I don't think you'll have a problem with Opti-2 at 100:1.