starting a four star 60 built with a ys fz 91. my question is how do i pick a motor mount (1) and (2) a prop? any suggestions would be great.

I'm guessing now but have you ever built or assembled a plane before?? Now you have me worried about the engine too. Have you ever tuned one? You buy a mount for a .91. If it's a great planes it will state on the package the engine range the mount fits. If it's an aluminum mount then it will state the size. Horizon sells some good ones. There is a prop chart sticky in building or beginners. A lot depends on how you want the plane to fly. I like longer props with a smaller pitch. I had two planes that went the other way to slow them down but I never gave it a lot of thought wondering why they broke the rule. On the 4* I would be testing a 15X4 or 6 right away but prop testing takes me a complete day until I find the prop I like. The engine has a working RPM range and you don't ever want to go over that and if you over prop too much it will lug it down. Just keep it in the working RPM range and you will be OK.

Hmm, 91 size 4c fuel injected engine

If the 4star did not come with a mount, you can try a GP mount 46-60 size. It will fit even though it is advertised as undersized.

For the prop, download / obtain the manual from the web if you dont have one and go for the recommended prop. I think a 14x6 would be good. If you are learning the hobby, go with Master Airscrew so you dont break it if you have a ground strike. There is a prop table somewhwre in RCU if you search for something like "which prop"

Ameyam

I am new to building and four strokes. I have tuned a 2 stroke but most of the members I'm my club fly four strokes so they can help me. I just didn't know how to pick the mount or which mount would work the best. I do feel more comfortable with the ys as I read everything you have said in previous posts and the answers I got from the ys sub forum.

Have faith I will do the ys right.

As I recall the last 4* 60 that I used a four stroke in was a Saito 100 and the GP adjustable mount for 90 size engines.

I used the GP adjustable mount on my last build with a .91 4s.  I didnt think I was gonna like it but it turned out pretty good.