rcflyer96

Ok guys, this is my firs 4 stroke and i'm still pretty new to this hobby. About 2 years. My knowledge in engine tunning is very limited and pretty much know how to do the low speed and high speed and thats it. I've got the 120SF mounted on a F90 and just tried running it for the first time. Starts very easy, easiest engine so far to start!! First run up and it throws the spinner, shut down re-tighten everything and try it again. This time it runs a bit better, tried the highspeed needle and i had to turn it in to about 1 thurn out from fully closed for it to run decent. It then threw the prop again. The things I noticed were that their was alot of fuel around the carb and needle when I was done, and the engine was running very hot. I've got no idea where to start; pump, low-end, high end, and why it throws the prop?? The needles may have been played with as the engine has been sitting for quite a while. If someone can give a basic intro for me I would greatly appriciate it. Fuel is 15%, plug is what came in it, I do have a OSF plug that I could put in it though, and prop is 16X6 K series, 2 1/2 inch Dave Brown spinner.

Thanks Alot!!

Dave Shadel

The engine has some problems which were caused by sitting. The regulator needs to be re-built if fuel is pouring out of the carb when the tank is pressured up.

Go to the instructions at www.ysperformance.com and try to follow them exactly. If you can't get the engine adjusted properly it needs to come see us.

YS Service
1295 Industrial Court
Gardnerville, NV 89410

Phone 775-782-4562

rcflyer96

The fuel isn't poring out just seems to be a bit, but I did notice some right by the needle valve. How do I know if their are leaks? Also what can I do about it throwing props?? I will try again following the instructions from the site tomarrow and get back.

Thanks

Dave Shadel

It throws props because it is too lean or going lean. Part of problem is fuel. Minimum 20% nitro and 20% oil. If you are running 4 stroke fuel it is a big problem. Fuel leaks cause lean problems as well. I recommend all new gaskets, 0-rings and regulator parts. Fix all these things before you damage the engine.

rcflyer96

Where can I buy the parts to do this??

Thanks Alot for the help.

Dave Shadel

YS Parts

775-782-4562, after 9am west coast time Monday through Friday.

Good Luck!

rcflyer96

Just would like to follow up on this thread, changed to 20/20 Cool Power fuel, bought a new OSF plug, and it runs like a champ!! Yet to maiden it on my F90 but thats coming soon. The YS has tons of power!!! Simply awesome.

Thanks Alot.




Chris

Dave Shadel

Great!

brianl1620

How do I tell if I have a ys f-120 nc or a ys f-120 sf

petec

My Feedback: (58)

Please start a new thread and post some pictures of the engine from both sides and the back. I'd like to keep the threads separate for those who are searching.