I've had outboards mounted on my TI for about 3 1/2 years now. We are scuba divers and tend to sometimes go pretty far offshore and down in Key West the weather can be unpredictable, and it can get downright dangerous out there with the gulf stream and very strong currents. Plus being just a tiny island out in the middle of the gulf, if you miss it your pretty screwed (next stop Cuba). Not the place to have a rudder failure, or run out of wind.
So as a safety precaution I have always had an emergency outboard motor mounted on the boat, very seldom used it, and only used it when all else failed and my life was in danger.
I had an Island hopper outboard mounted on the boat. This is the motor I had ( http://www.ioutboardmotors.com/20hp-4-cycle.html
). The motor weighs 20 lbs and as an emergency backup motor it did it's job, however over time in the salt water the motor pretty much rusted away and I began to worry about it, if you plan to use in salt water I'm not recommending to buy that motor.
I recently bought a new Honda 2.3 motor as a replacement for the aging Island hopper (which still runs, but it concerns me about all the rust and corrosion). I have to say I am really really impressed with this Honda motor, it appears really well made, and appears to fit the bill as a reliable emergency backup motor for me (something I can depend on in a pinch).
I am kicking myself now because when I bought my first motor, the runner up was the Honda (should have got the Honda in the first place in retrospect, but I wanted to save a few bucks).
Here is a thread about something I discovered accidentally while doing the ten hour break in on the Honda, also shows the Honda working, and some pics of the Honda on my boat. ( viewtopic.php?f=71&t=49014
Now granted I was just screwing around out in the water trying to break in the Honda (the first ten hrs your supposed to keep it under 1/4 throttle so it can break in). I discovered that by deploying my wing jib sail, mainsail (pulled tight), pedaling, and using the motor on low throttle all at the same time, I can exploit the tri power capabilities of the Tandem Island, and get incredible speed (for a sailboat) and fuel economy (somewhere around 100 miles per gallon if the conditions are right).
So I've been screwing around with that powersailing stuff for the last week or two, I'm sure it's just a fad for me, and will grow old quickly and the Honda will go back to emergency backup status. However I'm getting kind of fond of being able to go out all day and sail at really decent speeds (6.5 to 9mph) in low wind conditions (under 6mph) and it only costs me a buck or so in gas. One thing about south Florida is our winds are typically very light (< 5mph) so the TI typically only sails at 2-3 mph ( I can walk faster), and when it's 90 degrees out there it's an oven out there on the water with no breeze. Which is typical conditions 10 months out of the year.
I haven't ran the motor at full throttle yet (about half throttle max so far), and haven't ran it without my sails so I don't know how fast it will go without the sails (don't really plan to either). Though powersailing with the wing sail and mainsail I have had it up over ten mph (at half throttle max) several times in favorable winds ( >7mph). But I'm assuming 3/4 of the power is coming from the wing sail, not the motor.
I do know that with my sails furled (not down) when I set the throttle to 1/4 throttle, it propels the boat to between 3 and 4mph into a 5mph wind, in fairly smooth seas. Then when I open up both my sails and start pedaling (with the motor at the same constant rpm) the boat speeds up to between 6.5 to 7.5 mph (depending on the waves). You can take from that what you want, I have no clue what it all means, I just know I can go out and have a really nice fun day sailing for under a buck, and I'm happy.
I'm probably going out tomorrow, I'm going to do a 50 mile run to Egmont Key and back, I will try opening up the throttle with the sails furled, and see what it does. (I'm guessing it will do around 10 mph, but that's just a guess)
Hope this helps you