longevity of I/O's ?

BF

Lieutenant
Joined
Apr 8, 2003
Messages
1,489
Hi there,<br /><br />My dad has a ~'72 Glastron with 120 hp Mercruiser. It seems he's barely able to get 2 seasons out of the U joints and gimble bearing. He doesn't put many hours on it either (maybe 20 per year, probably less). His friend has a starcraft also with 120 hp mercruiser, that's about 5 years newer, that has had the outdrive u-joint/bearings re-done 3 times in the last 3 years (in that case, I'm not 100% confident in the maintenance/lubrication practices).<br /><br />Is this just par for the course? He's thinking about getting a different boat, but is definately leaning towards an OB because of all the hassle he's had with his current boat. The launch he uses is very shallow, so the boat has to be run with trim way up for 100 yards or so every time he launches... I thought maybe I/O's don't like that much (?).<br /><br />Do newer I/O's have better outdrives? To me, it seems that they still have U joints and gimble bearings, so they're likely subject to the same wear issues. Is there a particular type that is particularly renowned for being bullet proof? I've heard good things written about volvo's, but never actually talked to someone who has one. (they're much less common than OMC/Mercruiser around here). Certainly not seen much on smaller boats. <br /><br />thoughts?<br /><br />Brent
 

bomar76

Lieutenant Commander
Joined
Jun 27, 2002
Messages
1,963
Re: longevity of I/O's ?

Running the engine with the outdrive in trailer up will destroy the ujoints and gimbel in short order.<br />I suspect that is what he is doing.
 

brucec

Seaman
Joined
Jul 6, 2003
Messages
52
Re: longevity of I/O's ?

Whats the alternative in shallow water?<br />Is it ok to idle out?<br />Does it help any to bring it off trailer up a little,but still above trim up?
 

magster65

Commander
Joined
Sep 1, 2002
Messages
2,573
Re: longevity of I/O's ?

Unfortuately there is no I/O that likes to be run tilted way up like that. The u-joints won't last. An outboard would be more suitable for that kind of use.
 

BF

Lieutenant
Joined
Apr 8, 2003
Messages
1,489
Re: longevity of I/O's ?

that was my suspicion... but if the outdrive is way up, wouldn't the u-joints just be straightened out a bit compared to when it is in the "down" position. (It's more of a straight line from the engine crank down the outdrive). I guess the problem might be that the pivot points for the outdrive don't exactly match up at the U-joints (?). Is this right?<br /><br />Yes, and you've said more or less what I think, that OB's are mucho simpler because the powerplant is rigidly connected to the gearcase and adjusting thrust angle is done by moving the whole thing.<br /><br />Having said that, in what cases would an I/O be preferable to an OB? I'm thinking maybe for larger cruiser type where you want the torque of a V8 to cruise? Are there examples where a small I/O (a 4 or 6 cyl) would be preferable to a 4 stroke OB?<br /><br />Brent
 

Doug Durako

Chief Petty Officer
Joined
Nov 17, 2002
Messages
519
Re: longevity of I/O's ?

I like the I/O for a quite, smooth, stable ride.<br /><br />After a day in my fishing boat (outboard), I continue to hear the motor running/ringing in my ears for about a week, not to mention the horse voice I get from shouting at my passengers all day long.<br /><br />My neighbor is on his third brand new 60-horse 4-stroke outboard from Mercury in four years. He knows the regional rep. quite well. The latest one is on it's second season with no problems (yet).
 

magster65

Commander
Joined
Sep 1, 2002
Messages
2,573
Re: longevity of I/O's ?

BF, The drive doesn't work like that. At the top of it under the cap is a 90 degree upper gear set and the u-joints are between the engine and that gear set. They're in line when the drive is down (generally speaking). I feel the same way as ddboater, prefering the smoothness and quietness etc. of the stern drive but in this case that isn't ideal. An outboard would be better.
 

brucec

Seaman
Joined
Jul 6, 2003
Messages
52
Re: longevity of I/O's ?

does someone make a jet boat change for a merc<br />sterndrive?
 
Top