Hello everyone,
I was hoping that someone could tell me a little more information about the YS 60SR motor I have.It came mounted on a Akromaster airplane that apparently was new and never finished. There was no fuel tank or lines in the plane. I am very puzzled about the third pressure nipple on the right side of the motor and also on the muffler.The motor looks to have never been ran but turns over freely.</p>

Hobbyfun100,

The YS60 is a pumped motor. The third line is the pressure line back to the tank. The screw inb the bottom of the case below the carb is your regulator adjustment screw. This screw should not be moved. It is set at the factory and RARELY needs adjusting. You will also notice there is no pressure nipple on your muffler, because the motor doesn't need one. YS engines, like the one you have are incredibly powerful motors and are favored by all of us here in this forum.

There are many more knoweledgable guys here in this forum who can explain the motor better than I have, but it's a start.

If you don't want to worry the motor, just send it to me. I'll be glad to take it off your hands...........LOL

Whoa! Vintage YS - nice!

Actually, as mentioned, this muffler does have a pressure nipple. Now, modern aircraft YS have only two nipples, one to feed fuel from the tank and one to the air vent from the fuel regulator - they are both on the left side. This engine appears to meter the fuel separately from the carb design and perhaps solely through the regulator on the bottom.

As shown, fuel enters the regulator at the rearward nipple, is passed to the regulator and returned externally for feed to the carb - somewhat in the fashion of remote needle valve engines (e.g., OS FX series). The nipple on the right off the regulator is the pressure line to the tank vent - at least so I believe.

The nipple on the muffler is a little puzzling but I suspect they designed a generic muffler that could be used with other non metered fuel engines. In fact modern YS 2 stroke mufflers have the nipple tap riveted as there is no real use for YS mufflers today other than on their engines. I'd close it off with a metric screw.

I wonder what kind of performance this "SR" has compared to an FS or even the long strokes R & AR?

David

PS BTW, if that is a check valve and not a filter, it should go on the vent side to prevent fuel return to the engine. If its a filter, then I'm not sure if and/or how the engine runs without a valve...

Very nice engine! Late '70s version, probably one of the first production YS engines. Note the machined 2-piece case versus the later sandcast, 1-piece case. Also, the fuel delivery system looks like the older design (before YS made engines and just manufactured the pump/regulator assembly for other engines). As for the pressure nipple in the muffler; my only thought is that they intended it to be sold for other engines as well. The muffler mounting/adaptor plate also hints at the aftermarket sales possibility.
Mounted in an MK Akromaster?
-Will
PS It probably had excellent performance - it is clearly Schnuerle ported based on the casting port 'bumps' seen on the front,rear and left side of the engine. Is it ringed or ABC? I'm guessing: ringed.

The motor is ABC

Cool, probably '78 version. How tight is the piston fit at TDC (top dead center). The early YS engines had VERY tight fitting pistons when new and required a good bit of break-in (Mine needed about 60 minutes of bench time).

It is a very tight fit, I honestly would say I dont think the motor has been broken-in yet. If anything maybe ran for a couple of minutes. I have posted some pics of the piston and other angles of the motor.

More pics of the YS 60SR</p>

Anyone out there interested in purchasing this motor? I have it posted in the classifieds</p>