1989 mercury 90 hp 3 cyl making a clicking noise

rp75951

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Jul 6, 2013
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I have a 1989 90 hp 3 cyl merc outboard starts up and idles fine but when you put in gear it makes a clicking noise like something wrapped up in prop or around shaft, I pulled prop off and it is clear any help would be great.
 

oldman570

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Mar 25, 2011
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With the prop off, is the clicking noise still there? If so using a dowel rod as a stethoscope try to narrow down where the noise is coming from. A clicking noise can be caused from several things, and it can be something simple or a disaster waiting to happen. You need to know where the noise is coming from before you can even start to look into repairs that are needed. JMO
Oldman570
 

Faztbullet

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Mar 2, 2008
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Check the gear oil for metal particials as a chipped gear will make a niose under a load like in gear in the water.....
 

rp75951

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the motor only makes this sound when in gear in the water, I changed lower unit oil and there was metal shavings in oil.
 

Texasmark

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Dec 20, 2005
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the motor only makes this sound when in gear in the water, I changed lower unit oil and there was metal shavings in oil.
Metal shavings are commonplace in lower units, in fact the drain plug is usually equipped with a magnet to collect these guys. A little is ok, but if you pull out a wad of filings wrapped around your magnet, like the end of a Q-tip swab then you have something wrong. Course how long has it been since the oil was changed? The longer the more would be normal.

When exactly do you hear this noise and at what engine rpm? Is it present at around 650-1000 and leaves above that, or is it present all the time? Is it a constant uniform noise or is sort of random in the type of noise it makes? What type material and pitch are you running on your prop?

Reason for the questions is my 90 had what's called "clutch dog rattle" when I ran my high per. 24P SS prop. It only occurred in the rpm range I mentioned and if I put a lesser pitched prop on, like my 21, it wouldn't do it. Not uncommon in 3 cyl. engines.

Mark
 

Faztbullet

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If you can run the shaving between your fingers and not feel them its ok if chunky or gritty feeling the gears/pinion bearing is going south.....
 

rp75951

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Jul 6, 2013
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thanks for all the helpful comments, lower unit needs rebuilding for $1100.00 not gonna put that much money in this old of a motor.
 
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