Those motors are used a lot out here on the rivers. The biggest problem with an outboard jet pump is that you lose 30% of your HP right off the top. So a 50hp becomes a 30hp. This means you lose a lot of fuel efficiency. You also completely lose nuetral as the pump is always putting out water. Nuetral is done by finding the sweetspot between forward and reverse. Reverse is accomplished by covering the output of the pump with a cupped deflecter that reroutes the water. Due to the small size reverse buckets on outboards they usually have pretty poor reverse when compared to their inboard relatives.
A couple thoughts on Jet drives. They are extremely safe when swimmers are about. They are great for fishing as you don't have to worry about the lines hitting the prop (getting sucked up the intake is another matter!). They absolutly hate seaweed! IE: If you suck up too much you aint going anywhere untill you clean out the intake!
Now then, all my experience comes from driving my 19' North River with a Kodiak 350 V8 and 2 stage Kodiak Pump and a few rides in friends open sleds with big outboard jets. Here is what I learned about having a jet. First, I have never found a better handling single engine boat at a dock! Period!. I can litterally spin the boat on its center. And with careful work on the shift lever nearly move the boat sideways. All this without having to saw the steering back and forth everytime I change from forward to reverse. Second, that V8 is NOISY and THIRSTY. Any runs over 15 minutes and you better have ear plugs. In a full day of fishing I will typically go through 20 gallons of fuel. And much of that time is spent trolling on the 7.5 Honda. Having said all that I really wish a pump would work on the 27. But when I called Hamilton to inquire about it they flat out told me that the flat bottom would cause cavitation and simply wouldn't work :cry So I'll be rebuilding the Volvo I/O instead.
