The 53 and 63 are basically the same engine. The motor was bored out to give the 63. Now the new 63S with the regulator no longer part of the case of the engine is a slightly different motor but its built on the same chassis as the original 53. 53's are no longer produced and have not been produced since about 1997-1998

Weights are the same or within a few grams.

This engine will compete in the power department with OS 70's and Saito 72's It will for the most part pull like a really strong 46-50 2 stroke engine. Props sizes will be slightly larger than the 46 2 stroke. 12-7, 13-6 is a good prop for the 63.

for specifics got to

www.yspartsandservice.com

and go to the owners manuals. Weights, bore, stroke numbers and such are on the owners manual page #1

Also

www.centralhobbies.com has information on the various engines on their site as well.

Troy Newman
Team YS performance