I just so happen to have two old school heavy weights from the late 80's-early 90's in my possession. The first is from 1989, the OS FS-120E Surpass and the second is from about the same time period, the Saito FA-120S DP.

The latter is my personal engine and the former is a good friend of mines. Both have been overhauled with new bearings, timing set, and TLC provided. The OS could be for sale, but Rob might decide he wants to keep it. The Saito, will not be sold. But that isn't the purpose of this post.

I thought head to head runs under the same circumstances would be a fun thing to do today. Both were swinging the same Master Airscrew 15x8 prop, drinking the same brew Morgan's 5% Omega with castor added, and firing with an OS F glow plug. Both engines had been run prior to what is seen in the video, both tuned more or less perfectly.

As you can see below the Saito outweighs the Surpass by 2.2 ounces. The Saito comes in at 32.5 ounces and the OS is at 30.3 ounces. The video shows that the Saito out turns the OS as well; to the order of 750 RPM at WOT.

Figures
Saito Max 8670 RPM Min 2250 RPM
OS Max 7920 RPM Min 2550 RPM

Granted the low end RPM figures could be tuned to be lower but most folks aren't looking for how slowly an engine can swing a prop. The OS really could not be tweaked to provide any higher RPM, the next click of the needle resulted in a drop in RPM. The Saito, well I did not try to get more out of it.

Saito FA-120S vs OS FS-120 Surpass Comparison Run (7 min 3 sec)

When I saw this engine listed on eBay I knew I had to have it. The ad stated that it was new and the three pictures in the ad were not that clear. I sent a question attempting to confirm the condition. I got a response stating that the muffler was new, no carbon residue and no smell. I pulled the trigger as these are HARD to find, especially new. The price was $212 shipped.

Well when the engine arrived, it took all of 5 seconds to figure out that it was NOT new and never run. Holy hell! What have a done now? I asked. I made some videos, as I always do to document the condition. I sent a message to the seller explaining the condition issues and 3 days later I got a response. My request of a 50% refund for a non-new engine was granted. Oh, I forgot to mention, the engine was LOCKED up also. It would not turn over at all!

Well I was much happier knowing I just scored a Saito FA-120S DP for $112. I knew I could fix it and, I did. The end result was it just needed some cleanup and a new set of bearings.

Here is the video I made if it running today. It is a very nice $112 engine and one I will keep for many years.

The other disassembly videos are located on my YouTube channel.

Saito FA-120S DP The First Runs (12 min 59 sec)

...but a serious MF. This is an engine sent to me by a friend along with many other engines. The intent was to clean up, play with, make videos and then sell them. Well I have made it through many of his engines, but this one is a bit special. It is a Thunder Tiger Pro 120 two stroke engine. Now when it arrived it looked quite new with little run time. The only issues was that it was very tight turning it over when a propeller was installed.

I tore this engine down, pulled the new bearings and gave it a thorough inspection. When I re-installed the bearings, I made a stupid mistake too. I 'assumed' that the front bearing was fully seated when flush with the front housing. This was how I installed the front bearing using my arbor press. The crankshaft felt great and smooth before the piston was re-installed. It still felt great afterward, but it was a different story when the propeller was attached and tightened down. Eventually I dis-assembled the engine again and found a perfectly sized socket that would fit the outer race. It certainly seated another .5mm-1mm after that using the press. Issue resolved, dumb mistake made, lesson learned.

Now to run this thing! That was and is the largest 2 stroke engine I have ever attempted to run. Honestly I wasn't sure it would fit in my PSP test stand, but, luckily for me, it did. Well run it did! It has been one of the most fun engine runs I have had in a long time! The thing is big, scary, and powerful! I...Continue Reading

I bought this engine here for a mere $15 shipped. It was new, never run and without a muffler. I bought it as a piece to experiment with. It has proven to be much more resilient than I thought. See the full story in video.

https://www.youtube.com/playlist?lis...VOsUjeU0JgrH8G

I have a YouTube subscriber who has shown me some videos of a home brew fuel he makes with only Ethanol and castor oil. Where he lives in Germany pre-mixed glow fuel with nitromethane is quite expensive if even available. I have tossed around the idea of mixing my own fuel before, but never did because it really just isn't cost effective. I have a LHS that still stocks fuel at a decent price so why mix my own?

Well for an experiment I decided to mix some and try it out. This is the 'what if' scenario. What if all of my LHS closed the doors? What if I could not get pre-mixed glow fuel anymore? Well in this experiment I get an answer to the 'what if' question.

I went to Home Depot and bought a 1 quart can of Klean Strip Denatured alcohol. In addition I already have some Klotz BeNOL racing castor. I simply mixed 6.4oz of alcohol to 1.6oz of castor in a mason jar. I then just filled an 8oz fuel tank with this and selected two engines to run.

I choose my OS FS-30 Surpass and an OS 46 SF engine. I figured one 4 stroke and one 2 stroke would be a good starting point.

Well watch the video to see the results. It is quite interesting.

Home Brew Fuel Experiment: My 401st Video! (10 min 9 sec)

I bought this engine from eBay, paid a bit more than I should have, but hey I'm planning on keeping it so.... It looked pretty decent on the outside. it was missing a few items that added to the overall cost to me, prop washer, muffler, bearings, and the needle valve assembly needed to be replaced. Fortunately I had a replacement needle valve assembly on hand. I also ordered some gaskets, retaining nuts for the muffler and an O-ring.

Once I opened her up I saw how dirty the inside was! It took some time but I got it done and now she is a beautiful and fine running engine once again. See the story in video here.

https://www.youtube.com/playlist?lis...uApBaSyU0jaKcl