On all OS engines, the carb is held in place by 2 small screws. What size are those screws??? I have tried a whole box of screws and none fit. Need help pleae.

dc

I belive that they are 3mmx5mmx0.5pitch.

Cheers.

Dubro sells a package of nice 3.5mm socket head screws that you can cut off to the right length. My LHS has them right on the shelf. I suspect OS uses fractional sizes for their bolts so you can't get 'em at the hardware store like those 2.6 ones they use in the 15LA.

When I saw this thread I thought it was a duplicate of one I just answered over on the engine forum. Anyway, the screws are available from Tower. I posted a link, along with a short desctiption of how I found them, in the other thread http://www.rcuniverse.com/forum/fb.asp?m=3068748

Just remember that OS = Japanese = Metric. This applies to threads and the allen (hex) wrenches you should be using. Using the wrong (SAE) wrenches will quickly result in stripped sockets in the bolt heads when working on the engines.

Well as long as we are going into warnings those screws that look like phillips are actually JIS (Japanese industry standard) which is why they round out so easily when a phillips screwdriver is used. The JIS screwdrivers are available in sets if you want.

Yep, and that applies to Futaba servo screws as well.