Terrible outdrive noise,shake

smonoky

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Dec 17, 2004
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Recently bought a 1973 165hp,I6 mercruiser, had some minor problems that are now taken care of. I put in the water today and when I shift into drive or reverse there is a horific vibration in the outdrive, that was'nt there last time it was in the water. Hesitant on taking off the outdrive personally. Bought the manual, read past threads, haven't found anything. Simple or expensive?
 

Don S

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Re: Terrible outdrive noise,shake

Could you describe the minor problems that are now taken care of. It may very well have something to do with what was just done.
 

FreeBeeTony

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Re: Terrible outdrive noise,shake

I had the same situation 2 years ago........that awful sound/vibration.......Is it quiet in neutral? Mine only was noticable when it was in the water under a load.....it seemed smooth on the trailer on the muffs.<br /><br />If it is the outdrive.......my money is on the pinion gear.<br /><br />Hope I'm wrong............
 

smonoky

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Re: Terrible outdrive noise,shake

the minor problems were just a set of points and a coil. Yeah, it is quiet in nuetral and just a little throttle anymore and it does'nt sound good at all. Any ideas on how I can narrow this problem down? Freebee what was the outcome on yours?
 

Bondo

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Re: Terrible outdrive noise,shake

Have you pulled the Drain Plug on the Drive,+ Checked the Condition of the Lube ?????<br />You should be looking for Any Water, or Metal.....<br /><br />If you find Either, The rest of the drive Should be Disassembled for Inspection......<br /><br />Removing the drive is Pretty Easy.... 8 nuts,+ it's Off...........<br /><br />Disassembly is a Much More Involved Process.........<br /><br />I Still find it Hard to Believe that Tony Rebuilt his drive..... By Himself,+ Without the "Special" Tools.............<br />And,<br />It's run Perfectly for a Whole Season................<br />Tony's a Pretty Handy Wrench, for an old Brooklyn Boy................... ;)
 

Don S

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Re: Terrible outdrive noise,shake

What happens when you give it some throttle in neutral? I'm wondering if your vibration is a rough running engine.<br />What I am getting at, since you just changed points and coil and your problem started, did you recheck the dwell on your points? Did you reset the timing? You didn't mix up the spark plug wires did you?
 

FreeBeeTony

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Re: Terrible outdrive noise,shake

bondo.......I am very flattered by your compliment! How did you know I was from Brooklyn?<br /><br />My lower unit "blew". The pinion gear (in the lower unit) took-out the fwd gear in the lower unit.<br /><br />And yes, I rebuilt it w/o any special tools, and it ran fine all season. I replaced all the seals, u-joints and yoke also. When I drained the gear oil this fall it looked fine......<br /><br /><br />I tend to agree with Don S. Maybe it's running rough and it's not the outdrive.....<br /><br />If you still think it's the drive.......take it off and seperate it, remove the waterpump housing and impeller, you should then be able to turn the drive shaft by hand. It should turn smooth in neutral and both gears. Mine felt "awful" when I did this........That's when I knew it was the lower unit. My upper gears seemed ok, I just replaced the seals, yoke and u-joints in the upper and all gears bearings and bearing carrier in the lower half.
 

DHPMARINE

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Dec 16, 2003
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Re: Terrible outdrive noise,shake

Problem here is one mans horrific is another's norm.Unless the drive was at full tilt during the lake test,I'd get the drive off and check gimbal bearing and u-joints to be sure.Parts for those I6's are getting NLA,and a transom housing would not be cost effective anyway.(on a 1973 boat)<br /><br />DHP
 
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