I have to ask the OP: do you want to do this for a living or just as a hobby/extra income? I've enjoyed working on mechanical things since I was a kid and was a car mechanic for my first career. When you have to depend on an activity for a living the fun factor goes way down and the stress and BS goes way up. Learning on the job is a pretty rough way to start out. You'll either be doing busywork and mopping the floor or struggling to turn out finished jobs because you don't yet have the experience or training. Yeah, I've been there and it SUCKS.
If you are seriously thinking about doing this for a living I would advise you to see about getting a part time gig with a small engine shop. Work at it awhile and see if you like it. Be sure to have an honest talk with fellow techs about what kind of income you can expect and what kind of responsibilities you'll have. Be advised that, at least here in the states, your job benefits such as health insurance and vacation are going to be very modest and many small shops offer none at all. Finally (as if I haven't rained on your parade enough) you will be expected to work on anything that comes through that door, not just chainsaws. This may include trucks and ag equipment.
I'm really not trying to talk you out of it, I just hope you will carefully study this before you decide to change careers. After 10-1/2 years working on cars, mostly as a Toyota dealership tech, I hung it up and got an office job.
I should have changed the title of my thread....definitely not into in to make money...the way I see it, my new found interest is going to cost me money....at this rate lots.
I reread you post and substituted every time you wrote mechanic with stock broker......I couldn't have written it any better if I was describing my first career (except the benefits part). After 10 years as a broker I quit that because fun & money were not there...I hear what you're saying and truly appreciate the input....If the passion goes away, I'll get rid of the saws (in working order).