Grinding going into gear

jtexnm

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Dec 24, 2022
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My 1977 Mercury 1150 (I checked the serial and it's not a 1976) makes a loud grinding sound when shifting into either gear, and there is some resistance along with the sound.

The issue is not shifting slowly. Do I need a new lower unit? Anybody have ideas of anything to check?
 

QBhoy

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Mar 10, 2016
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My 1977 Mercury 1150 (I checked the serial and it's not a 1976) makes a loud grinding sound when shifting into either gear, and there is some resistance along with the sound.

The issue is not shifting slowly. Do I need a new lower unit? Anybody have ideas of anything to check?
Take the prop off and try it. If you’re out the water and on the trailer. And not used to how it sounds…they will make a fair old noise shifting into gear. Obviously check there is oil in it too.
 

jtexnm

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Dec 24, 2022
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Take the prop off and try it. If you’re out the water and on the trailer. And not used to how it sounds…they will make a fair old noise shifting into gear. Obviously check there is oil in it too.
Since I'm refurbishing the boat, this is on the trailer with muffs. I'll try with the prop removed when I get a chance.

The sound is what happens when you shift a manual transmission car without depressing the clutch: grind/clunk. It's very similar to that sound.

There's good oil.

Thanks.
 

QBhoy

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Since I'm refurbishing the boat, this is on the trailer with muffs. I'll try with the prop removed when I get a chance.

The sound is what happens when you shift a manual transmission car without depressing the clutch: grind/clunk. It's very similar to that sound.

There's good oil.

Thanks.
Ok. They do make a noise like that going into gear. Especially out the water. It’s a straight cut dog, as you’ll know.
 

jtexnm

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Ok. They do make a noise like that going into gear. Especially out the water. It’s a straight cut dog, as you’ll know.
Pardon of my ignorance but what do you mean that it's a straight cut dog?
 

QBhoy

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Pardon of my ignorance but what do you mean that it's a straight cut dog?
There is no clutch, if you like. It’s a dog clutch arrangement. Gears are harshly engaged. The effect is far worsened if there is any play in the cables at all. Need to be really well set up and when engaged, a positive and confident action is required at the remotes. As you’ll likely know anyway.
 

racerone

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Dec 28, 2013
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Pinion gear and forward / reverse gears are all turning when motor runs.----The clutch dog slides on the propshaft and engages the turning gears.----It is violent and makes noise.
 

jimmbo

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May 24, 2004
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Clunk or clang, is okay, but any chatter/grinding, and you are shifting way too slowly, the unit is either In or Out of gear, no easing it. On the those units, the Forward Gear and Dog have ramps, the Reverse Gear and Dog, have Straight Teeth/Recesses
 

jtexnm

Petty Officer 3rd Class
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Dec 24, 2022
Messages
75
Clunk or clang, is okay, but any chatter/grinding, and you are shifting way too slowly, the unit is either In or Out of gear, no easing it. On the those units, the Forward Gear and Dog have ramps, the Reverse Gear and Dog, have Straight Teeth/Recesses
I take it then in most cases the noise I am hearing is because somebody is shifting too slowly. But I have plenty of experience shifting with an outboard. This is definitely very different from anything I've ever heard/felt with a boat before.

This is my third boat that has an outboard. I never worked on my other boats because I could afford to pay somebody else but now I've got to do it myself. And since I bought this one, which I've only had running on muffs on the trailer, it's made that loud grinding noise when shifting. I tried shifting it as hard and fast as humanly possible and that doesn't make a difference.

There is resistance as it makes that noise so it's clear something is contacting. I was imagining that maybe the dog clutch got ground down or something.

Any ideas?
 

jtexnm

Petty Officer 3rd Class
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Dec 24, 2022
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Pinion gear and forward / reverse gears are all turning when motor runs.----The clutch dog slides on the propshaft and engages the turning gears.----It is violent and makes noise.
I expect the clang of metal hitting metal but I'm concerned about the grinding sound. Have you ever heard of that? And not when someone is just shifting slowly.
 

jtexnm

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Dec 24, 2022
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There is no clutch, if you like. It’s a dog clutch arrangement. Gears are harshly engaged. The effect is far worsened if there is any play in the cables at all. Need to be really well set up and when engaged, a positive and confident action is required at the remotes. As you’ll likely know anyway.
I have been wondering if it's some kind of misadjustment in the steering cable. But when I read some other posts, it seemed like that would explain grinding in one gear more than both. So it left me unsure.
 

Lou C

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If the shift cable/linkage is sticky it will have the same effect as shifting slowly.
 

racerone

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If you feel there is something wrong then take it apart for inspection.----Control box / cables / linkages / lower unit.----All quite simple really.
 

jtexnm

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Dec 24, 2022
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If you feel there is something wrong then take it apart for inspection.----Control box / cables / linkages / lower unit.----All quite simple really.
That seems like good advice. I don't feel like I know what to do or look for beside the suggestions from folks
 

jtexnm

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Dec 24, 2022
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If the shift cable/linkage is sticky it will have the same effect as shifting slowly.
Interesting. So that's where the cable coming from the controls meets the linkage under the cowl?
 

jimmbo

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May 24, 2004
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Too much Preload on the Throttle Cable can make for less than good shift action too.
Just out of Curiosity, what Rpm is the motor idling in neutral?
 

racerone

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We can only go by your verbal description.----Nobody can see , feel or hear your motor.----Post a video of it running.
 
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