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Trouble with Mercruiser Alpha 1

After shifting our boat into gear, we get a clunking sound. We have play at the prop shaft. Heavy vibration when driving the boat slow.

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What is the order of assembly(fiber washers and steel washers) for mercruiser i/o front engine mount
Ihave installed incorrectly and have excessive vibration?

Posted on Jun 13, 2010

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Time to get rebuilt
i would not run it again til a pro lays his hand on it and tells you otherwise
hopefully it is still rebuildable

good luck

Posted on Jun 25, 2009


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1 Answer

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the gear shift shaft/rod pushes down on a metal wedge inside the gear box this forces a dog clutch to engage a gear and transfer the engine drive to the prop shaft along the prop. A return spring keeps the dog clutch against the wedge so that when the shift shaft/rod is lifted the dog clutch disengages (neutral) if you keep lifting another gear is engaged, astern. Missing one of the gears, adjustment. No gears, shaft/rod alignment. Is yours direct mechanically hard linked or does a cable transfer the movement to the shaft? Check the top shift connections first, before taking the leg apart again.
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Took prop off of alpha one 2007 v6 mercruiser and the shaft still turns in gear and makes a clicking sound inside lower unit?

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GET IT TO A MECHANIC!! Something is loose or about to collapse! Remember that vibration and noise can travel away from the source so get the mechanic to start in that corner.
You need to get the following checked!
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-Prop shaft mountings at differential.
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When i slow down to 20 mph as it shifts down it clunks. and as i am parked and i try to put it in gear it makes the same clunk sound.

it sounds like you may have a bad universal joint in one of the drive shafts,more likely in the main shaft that runs from the transmission to the rear differential.

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