Instruction: Evaluate the answerability of a question by analyzing the related document, outputting yes if the document contains information addressing the question, and no otherwise.

Input:
Question: Is it a 15' or 20' shaft?
Document: Works amazingly, my brother is very satisfied with it. Got it in 3 days from CHINA! Runs smooth, quiet, pumps water great. High quality motor for a generic brand. It even came with a tool kit~
Unfortunately we had to return our outboard, SHANGWEN was excellent to work with, and made the return easy to do.
I have had this for one summer and used it in salt water. I usedit once a week on a boat rated fir a 10 horse and he no issues. Same as an older Yamaha two stroke only with a cheap plastic cover. I bought this for a spare. Now I use it all the time.
Best I can tell, this little outboard appears to be a Chinese copy of the old Yamaha two stroke. Replacement parts and fuel connectors appear to be compatible with Yamaha. Starts on first or second pull, so I'm happy. I would have given 5 stars except for the fact that shipping invoice included instructions not to leave negative feedback. The note basically said that leaving anything other than 5 stars would void my warranty. I don't like that, so I'm only leaving 4 stars.
Answer: no