help with Smaller YS 4 stroke - RC Groups
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Oct 05, 2012, 05:46 PM
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help with Smaller YS 4 stroke

I bought a used 4* 40 and it has a YS 4 stroke on it.
Been trying to figure out what size it is. It came from an estate sale so no way to ask previous owner.

It spins pretty freely but I have not tried to start it.

The guys in the club said to just get rid of it. Haven't found much info on the net.

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Oct 05, 2012, 06:39 PM
jeffie8696's Avatar
I dont know why you would get rid of a good YS four stroke, they are a very high quality engine.
Oct 05, 2012, 07:20 PM
TCBlightning's Avatar
Post a picture or check out the Central Hobbies engine page. They have pictures of all the engines there. My guess on a 4*40 would be a version of the 53 or 63 and that is a lot of power for a 40 size!

I have the 63FZ-S on my Ultra Stick 60 and it has pleny of power.

Oct 05, 2012, 08:37 PM
Hope to get out of life alive
kenh3497's Avatar
If you get rid of it, I'll take it Well at least until my bookkeeper (wife) finds out

Oct 06, 2012, 12:15 AM
Registered User
Thanks for the replies.... I pulled it off... It's an fz53.. I gotta be honest. I've never ran a four stroke. It just seems hard to find info on The YS stuff... Is there supposed to be a low speed needle on these engines? I see threads in the end of the throttle barrel but no screw?

I also recently picked up a heli with a YS .61 st-2 motor and can't find any parts listed for it...

I've only had two nitro planes before this. My trainer, an Alpha 40 with an evolution.46 and a Midstar 40 with a Super tiger .45

I pulled the YS off of the 4* and also pulled the fuel tank out of it. I'm glad I got to digging because the fuel tank had a hole rubbed in it from the engine mount screws being too long.

Thanks for the tip about central hobbies.

I belong to a club but seems like they're either flying electrics or giant scale..

Again, I appreciate the help!
Last edited by johnnyV52; Oct 06, 2012 at 12:18 AM. Reason: dumb thumbs hit enter too quick.
Oct 06, 2012, 06:45 AM
Registered User
I TOBOR's Avatar
John, not all of the .53s had a LS needle, I had (3) .53s at one time, two had LS needles and one did not. The parts cost $35.00 to upgrade buts it it works fine without it.
Oct 06, 2012, 08:10 AM
Methanol, The Cool Fuel !
Gary Cee's Avatar
Put me in line after Ken ! The YS is a very fine , sweet running engine that will easily out power other 4S engines of similar displacement and weight .
Oct 06, 2012, 12:18 PM
jeffie8696's Avatar
YS engines are supercharged.
Oct 06, 2012, 12:52 PM
Registered User
Dang,you guys got me all excited this morning... So how much pressure do they put on the fuel tank? The tank in plane was wrapped in fiberglass strapping tape. Is this done just as a precaution? Doesn't look like it was sealing a leak. The tape is all still firmly attached.
Oct 06, 2012, 01:16 PM
Methanol, The Cool Fuel !
Gary Cee's Avatar
The pressure is often reported at upwards of 8 PSI . Most of the YS I have encountered ranged closer to 5 PSI than the quoted 8 or 9 .
The YS is very slightly supercharged and runs fuel injection at throttle settings above idle . Other benefits , aside from the awesome power are the ability to place the fuel tank back at the CG so there is no CG shift during the flight . The engine gets far better lubrication and cooling . The entire fuel/air mix travels through the crankcase . Other four strokes rely on blowby oil to lube the bottom end . By pulling the charge through the bottom end , the bottom gets fresh oil and fuel to cool and lube . The charge is now better vaporized for better efficiency . This means less fuel for a given power and better transition . It also means that the case gets better venting and tends to collect a lot less moisture and crud and the problems that go with the crud .

The YS is a very well made , high quality engine . The designers did an outstanding job . YS engines are a bit different to run but once you learn them , they are a very satisfying engine !
Oct 06, 2012, 04:53 PM
Hope to get out of life alive
kenh3497's Avatar
Originally Posted by Gary Cee

YS engines are a bit different to run but once you learn them , they are a very satisfying engine !
That is a very true statement. I am starting to get the feel for how mine runs. I've learned you can't just crank on the needles. You have to have a bit of finesse. It seems they are also a bit more fussy about not having any gaskets leaking also.

My 53 is only the second four stroke I've owned. My other is an Enya 90. They are about as opposite as you can get in operation and "handling" as you can get.

Good luck with your 53!!

Oct 06, 2012, 07:18 PM
Registered User
I TOBOR's Avatar
In my mind they are more than slightly supercharged, it's along the lines of 33 to 35% when you consider that the FZ .91 was equivalent to most 1.20s when you could get one to run right.
Oct 06, 2012, 07:53 PM
Methanol, The Cool Fuel !
Gary Cee's Avatar
The yS 91AC and 1.10 are extremely good runners . Very solid performers after the initial set up .The YS power gains are more than just the supercharging . As mentioned , the improved lubrication, fuel injection and vaporization add a good lump of power .

Ken , It sounds like you are getting on top of your .53 . The rush to adjust makes trouble for many first timers . Being able to accept they are a bit different and adapt is a big step . Not at all difficult but they are indeed different in many ways .
Oct 06, 2012, 08:05 PM
Registered User
ken78cvx20's Avatar

Ys 53


Take a look over at (The R-C Proving Grounds ) more info on YS engines

I am going to try a ys 53 on my GP Escapade 40 saw one flying around on U-Tube moved right along.

Oct 06, 2012, 11:11 PM
Registered User
Hey thanks for the tip.. I run Omega 15% the pink stuff in my 2 strokes... Will that work in this? I know some of the guys who run 4 strokes in the club use Cool Power...

Ahh I also started flying heli's about 2 years ago... Good for the brain... Just got my first used nitro heli a few months back.

Haven't done anything with it yet. It's got a YS in it and came with a spare. Not sure what kind of shape these motors are in as I have not run either one.

They are 2 stroke YS .61 st-2 motors. My problem? Too much time and not enough money... Heart attack at 46 and major heart surgery put me on early retirement.

Would the 53 work on a 3d plane like the Hangar9 twist? Couple of people in the club have the Twist and just have a blast with them.

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