Having 3 of the fs-52 engines for many years, the first thing I did was tear down the new alpha before the postman made it down the street to my neighbors and around the corner!

My impression is that this is more than what other mainstream four stroke brands (non YS) do in a "new" engine It's not just "a bigger engine in a smaller case with the same bolt pattern" and it's not just the same technology with a different displacement. Here are some of the differences I see so far.

On my scale it measured 415 grams (14.6 ounces) and the muffler is 40 grams (1.4 Oz).

It will take time to tell how the new lubrication system will work, but I like it so far! Shouldn't be hard to tap a crankcase vent if someone really wanted to divert the system.

The carb is the easy to adjust and very reliable 40N model from the .52, the new intake stack mounts by a set screw... so it can be added to the .52 if you like. And other carbs with a 10mm neck o.d.

The camshaft is listed as the fs40/48 part #. Maybe someday I'll run a profile and see what the difference is.

The crankpin and wrist pin both are a bigger diameter! Though I've never had problems before.

The rear bearing is a completely sealed unit and the front is metal shielded.

Brass head gasket is .007" (.18mm)

The 56a has a noticeably larger intake tract compared to the 52, and the valve springs are MUCH stiffer (will help attain a higher RPM), two things I've been doing to my 52's for a couple years now, a very welcome addition.

The exhaust valve is larger in diameter, intake seems to be the same. However both have longer stems than before. The valve seat angle seems different, or maybe I just need to clean my glasses.

The new muffler looks like the orientation is very adjustable that will be nice. It can also be used on the .52, or anything with a 10x.75 thread.

The head no longer has brass/bronze valve guides and seats. The head is all aluminum alloy, however the combustion chamber shape is the same as before.

Am I missing anything? hehe

Overall my impression is O.S. deserves a pat on the back for always trying to improve on our model engine technology, it seems so far the changes they have made are for the better.

I will probably still use my mix of Marvel air tool oil and ATF into the fuel line while running the starter each time I'm done with it, old habits are hard to break I guess. Sometimes we never know when we're going to fire up a particular model again, some sit around for a couple weeks, some for years... so I just do it to be safe.

It's going to take some time to run through all the props I've got and get numbers on it.

Let's not use this as a O.S. versus the world thread please... no bashing...