Hello Mr. Troy, I have a few questions about the 91ac. This is the only YS i have and it's kinda Greek to me, it's a rebuilt one from two crashed ones. First what are the setting for a first start? needles, and regulator? At the moment I've got Powermaster YS/Saito 20/20 in it and is runs, I will be going back to CoolPower when it's gone. I use the ProPattern 20 in all my 4stks. What size props should I run? I'm at sea level here in Texas, I have a 14x10 on it at the moment but no rpm readings. What surprises should I expect from this engine? I hear it's a hoss, and it's going in a H9 60 Mustang. Oh also how important is an exhaust? was going to just run a strait pipe, (tip from Richard Le), and the exhaust port threads are trashed.

The pro-pattern 20 is an excellent fuel in the YS engines. This is Cool Powers blend for 20/20. You can also run the CP 30% heli...

The 14-10 is a good prop to start with....You want the engine to turn int he mid 9000 range like 9400-9700rpm SO pick a prop and fuel gives you this for the High end rpms.


The HS starting point should be about 2 turns open...Should lean down to about 1.5turns...The regulator should be flush with the case,a dn the low speed air bleed screw should be about 1.5 turns open from full closed....

Go here for some basic instructions on how to run it....


http://www.probuild-uk.co.uk/factsheets/ys_engines.php


A straight pipe will work it will be very loud...you don't want to be the guy that cost your club its flying site.......


Troy Newman
Team YS

Thanks Troy, and please trust me it with a strait, it still won't be the loudest plane there. It's really not to different from my quickie 428 planes, as far as noise. Thank You again.

Hey Troy, another question, got it running and flew it, man, power for days!!! But sits and drips fuel from the carb, looked to be leaking around the barrel. Any idea's? Oh also who do I contact at Morgan about getting fuel from them. If ya want I'll pm you with more info.

Could be the throttle barrel seal...but chances are unless you are actually seeing ti come from the throttle barrel its not leaking there. It could be dripping from the carb and running down along the side of the carb body and looks like its coming from the throttle barrel.

I would try close the regulator about 1/8th a time for maybe 1/4 to 1/2 turn and see if you can get it to stop dripping and yet still run and transition properly.

Leaning the reg to much will make it detonate in the midrange so beware of this.

As for the fuel Morgan Fuels are carried in most hobby shops. If you have trouble getting it via a Hobby shop then we can work that side of things. However Morgan Fuels is very good about supporting the local hobby shops.

Troy Newman
Team YS

Troy, I need help with my 91 ac. I put a new cam and a new crankshaft in it.Now I tried to start it but it is not getting fuel to the carb.I tried a diff. motor and it fired right up, so I know the tank is ok.What needle do I have to ajust to get fuel running? Thanks alot, Guy

Well there are many possible options that range from not getting the cam in the right timing, to not getting the Crankshaft seated into the disc valve.


Assuming you had all this correct....

Try cleaning out the regulator. When the engine sits the fuel/oil in the regulator will gel up as the nitro and methanol evaporates. This will leave a thick gel like oil in there and its difficult to move that stuff through.

So take the regulator off and pump raw fuel through the passages. Wash the parts with raw fuel. Also make sure you install the regulator correctly. There is an index mark or protrusion on the regulator body. This bump goes toward the prop.

Next thing is remove the HS needle and pump raw fuel through the needle valve seat. This will flush any gunk out of this area. Once you do this it should get fuel.


Troy Newman
Team YS