I've got an early model 270. By early model I mean it has a 15" D short hub prop. Later model 270's, 280's and I imagine 290's have 16" D long hup prop. And no you can't put a long hub prop on a short hub and vice a versa. The prop shafts are a slightly different length. That is one slight difference in the 270's. All in all they are very good legs. The leg oil is very easy to change. Mine takes 2.8 L of 10/30 or 10/40 motor oil. The raw water pump is mounted on the engine is either belt driven or mounted to the crank. This makes it very easy to change the impeller or the water pump itself. The "achilles heel" is/are: the u-joint bellows is fairly large (compared to mercruiser) and can be prone to pinhole leaks. If you get a leak the intermediate bearings get ruined and to fix these you need to remove the leg and take the motor out to get at these bearings. Been there, done that. One trick I've learned to warn you of this problem is to put a small amount of oil in the bellows so if you get a leak there will be a small oil slick around your leg. The other issue can be the lift motor. It is an electromechanical system. There is a electric motor which turns a worm gear. The problem is when you want to go in reverse the leg HAS to be ALL THE WAY DONE AND LOCKED otherwise it kicks up in reverse. This can make getting away from a beach or other shallow water quite tricky sometimes.
When checking the leg out first thing is to unscrew the dipstick on the top of the leg and have a look. More important is after you sea trial the boat unscrew the drain plug from the bottom and see what comes out. This will let you know if the leg has any seal issues or not.
The other thing to ask is when was the last time he changed the u-joint bellows and greased the u-joint bearings. Every other year is a reasonable time frame. This will also let you know just when the last time was that the leg may have been removed.
They are actually a very simple leg to work on. I've taken the Seloc and Chylmer books out from the library and been able to all the work myself.
The only other thing I can think of is during hard turns you will hear the u-joints growling a bit due to the full turns but this is normal. They should be quiet during straight driving applications. I've changed prop shaft seals, re-sealed the whole leg, changed a few bearings and bushings, all this from a guy who isn't a mechanic. I make it sound like the leg is a lemon but I think the fact that a novice can fix it makes it a winner.
Hope this helps.
Dave
