FZ53 or FZ63 What's the difference?
 

I purchased a YS engine as an unknown size. Looked like an FZ63. Was told by an "Old Timer" that it was an FZ53. Looked up the manual and spec sheet for both.
DOH!!! They both match every measurement on the outside! I do not want to tear down the engine to measure the bore. (FZ 53: bore 24mm, stroke 19mm- FZ63: bore 26.16mm ,stroke 19mm) . Is there any outward visual clue that I may have missed?? Thanks, Best Regards, TJ

RE: FZ53 or FZ63 What's the difference?
 

Look at diameter of crankshaft, in my 63 it has 8mm and in a 2nd hand 53 that I bought had a 6.25mm crankshaft... but was damaged and was subtituted by a 63 crankshaft.
This can help you but I don´t know if late series of 53 had the 63 crankshaft..

RE: FZ53 or FZ63 What's the difference?
 

Thanks spanishflyer , I'll mic it in the next day or so. I am going to use it as it fires right up and idles very nicely, and the transition is wicked fast,it also has an APC 13x14W and seems to pull like an animal,(it is in a .46 size trainer with no wing) so it doesn't really matter which it is. I just want to know for my own curiosity. Thanks again, TJ

RE: FZ53 or FZ63 What's the difference?
 

13/14???? Wow..
I use an apc 13/6 and obtain 11200 with 63 and 10100 with 53..
They are awesome engines..

RE: FZ53 or FZ63 What's the difference?
 

spanishflyer , I used to use an APC 12x4W on my Saito 82. hauling a Funtana 40 around. I have always heard the YS engine is more powerful for its size than comparable engines. I actually had a YS 110 for two years and heard so much about how finicky and cantankerus it was that I never used it.. ended up selling it.. I really regret that. Like I said , I got this one as is, in a trainer with no wing that had been sitting for years. And just runs so well, I gotta use it...maybe the 13x4W would be good on a 3D! Best Regards, TJ

RE: FZ53 or FZ63 What's the difference?
 

Had a ProBro tell me how to find out what I had...."Should be a stamp on the outside edge of the mount that says FZ53 or FZ63."
Cowl hid it, so out came the engine.. there it was.... just like he said.. It is an FZ 63. Yeeehaaww!!!now just gotta get me a 40 size 3D machine.. Best Regards, TJ

RE: FZ53 or FZ63 What's the difference?
 

You're welcome.
I've seen a lot of YS engines and I've never seen one of any size without the stamp on the outside edge of the mount lug.
The best prop for that motor is a Xoar 13x4 or MAS-K 13x5 for sport or 3D. For pattern type planes you might like a 12x7 or 8.