I bought a YS-91-C for sport flying on a Sig Hog Bipe.

I bought an OS-F plug, a Zinger 14X6-10 prop for break-in and a Zinger 15X6-10 for after break-in.

Now for the hard part, what fuel???

I have been reading for some time now many debates over synthetic; castor; synthetic castor combination.

Every engine expert, every fuel expert, and everyone inbetween all have very different opinions of what is best.

The YS manual states 15-20% synthetic or castor or a combination can be used.

What oil do you recomend and at what percent min. / max.

Also is 15% nitro okay for sport flying, I know most people use 20% but I do most of my flying about 1/2 throutle most of the time anyways.

Thanks for any help in this matter,
Tim

Powermaster YS blend 20/20 is the fuel of choice for the YS line. You have the right plug OS-F. Be careful you don’t over rev with a 14x6 prop. That engine can handle a 14x10.

Use a good quality fuel with a minumum of 18% oil, synthetic will work the best since it will keep the motor nice and clean. Castor has a tendancy to gum up in the regulator.

You can use 15% nitro but you will get much better performance from 20%-25%, or even 30%. Prop the motor so you spin 8500-9000 on the ground.

F plug is a good choice. After break in you will likely need to reset the valves.

Enjoy

AV8TOR,

Yes, the YS 20/20 does seem to be the choice of many. I was hoping to find an alternitive that I could buy locally so I would not have to mail order a full case.

As for the prop it is not a 14X6 but a 14X6-10. The pitch is 10 near the hub and tapers to 6 at the tip.

Thanks to both for the replys, I posted in the "YS engines support" hoping to hear from Dave S. on what other fuels he would recomend, if any.

Thanks again,
Tim

YS recommends 20% nitro and 20% oil in all of it's 4 stroke engines. Many of the top fuel manufacturers sell this blend known as YS 20/20. In warmer weather some of the YS engines will do ok on less nitro. Our recommendation is to go easy on any castor oil in the fuel. A couple of percent is OK, but any more is asking for regulator problems. Those of you with corporate funding may want to try 30% Helicopter fuel. Hard on the wallet, but very addictive!!!!

Wonder,
You have the east coasts largest manufacturer of glow fuel near you. Give S&W a call or look in most of the eastern PA hobby shops. His 20/20 is a true 20/20 all synthetic and is an excellent fuel.

http://www.s-whobby.com/prices.html

Fuelman

Dave,
Thanks for the info. I will go with the 20% nitro 20% oil. I am leaning towards 18% synthetic 2% castor.

Fuleman,
Thanks for the web site, I e-mailed them about shipping cost since they are 5 hours away.


Tim

Dave

I have a new YS63 and have tried everything to start the engine. Do you have any suggestions?

What does the engine do? I need a bit more info. Dave

Dave:
Back to the fuel. I'm using Cool Power 15% 4 stroke fuel and my 91 runs like a dream. Is this good??
Thanks!

If it works for you, that's fine. If you have problems when the weather cools off, raise the nitro content of the fuel.

I run my YS91FZ on 10% nitro (its very expensive stuff in Britain!) and get 9000 revs on an APC 14x10 at absolute peak. Motor is still not run in, had about 7 tanks through it so I back it off a few hundred revs at the moment.

Harry