Re: Johnson dura jet/military issue
I don't have experience with the durajet, and am looking forward to hearing about them also.<br /><br />As for regular outboard jets (Outboard Jet Company), I've used them quite a bit. You shouldn't get too hung up on efficiency because there are some very large operational beneifts which greatly counteract that loss. Less fuel efficiency yes, but given the right application, hugely greater operational efficiency.<br /><br />Yes, they put out less HP out the tube vs. the same engine with a prop, and therefore potentially burn more fuel. I'd say the estimtes of 25-30% loss are probably accurate. However, if you need a jet, you need a jet. I run a jet exclusively because I run in shallow water. If I were going through a couple of props a year, I'd definitely consider a jet. You'd need to go to a 50 to get what a 30 puts out with a prop.<br /><br />Upside is that they are super simple to maintain and give you some safety improvements and a lot of flexibility in operation. No lower unit gear lube. The only regular maintenance is simple, quick periodic greasing through an easy to access zerk, literally a 30 second job. The only other maintenance, really is servicing the propulsion impeller, maybe once a year. It is easy to "re-shim" (which adjusts the impeller for wear on the housing wear ring), and to sharpen. 30 minutes total -shimming and sharpening. I've done both and I'm no mechanic. <br /><br /><br />Operating is safer and easier than a prop. Very little, if anything, to break. Sits even with the bottom of the transom so if you keep your hull off the bottom, the jet is off the bottom. Very easy to beach and launch, load and unload trailer. No need to tip up for trailering. Very safe around swimmers or waders because no external prop. Less harm to coral and other underwater stuff if you're conerned about that. No risk of line being wrapped around prop. No gears (reverse is a mechanical cup which goes over the pump redirecting force), therefore operating between forward and reverse is quicker and easier than prop - no grinding ever.<br /><br />Another negative you hear is that jets are less maneuverable than props - I just haven't found this to be an issue - if it is, it's not a major issue.<br /><br />I would be surprised if the Dura Jet is a lot better - I've just never seen them in operation. Around here about 75% of the outboards run jets, and so far the Dura Jet just hasn't been used. Maybe they're just for lower HP outboards?
