Chris Craft 140 mercruiser stern drive problems

Joined
Aug 21, 2018
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I have a 1985 chris craft scorpion with a 140 4 cylinder engine the gears on my old sterndrive are destroyed and i purchase a new stern drive, it came out of a boat that had the same motor as mine, but when i went to insert the sterndrive, it did not wanna go in, i looked at the shaft i think is called a yoke, and it was different size, so i replaced it with my old one and still i couldnt get it in. i looked at the stern drive to see if they where the same and they are not. this one had a silver sticker and my old one had a red sticker???? can someone help me please
 

greno

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Nov 23, 2012
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Welcome to the Forum!
What year boat did the purchased sterndrive come out of?
 

greno

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Nov 23, 2012
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Ok, did you make sure that you had the shifter in forward and the outdrive shift shaft lined up straight while trying to insert the drive? It won't go unless you do that.
 
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Aug 21, 2018
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when i picked it up it was not on the boat the guy was just selling it for parts and he said when he bought it, they told him the sterndrive was new so im thinking maybe is for a different boat?? i looked up one that looks alike and it might be a bravo??
 

greno

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If it's a bravo it has a different shift mechanism than an alpha. You won't see the same lower shift shaft that you have on your old alpha.
 

greno

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You may have the driveshaft splines misaligned to the coupler. Try rotating the prop shaft while you are inserting the drive.
 
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how can i tell what model it is? the shift mechanism seems the same but the sterndrive casing seems different it looks longer in the part that connects top to bottom but the upper casing looks the same
 

greno

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Ok, as suggested, please post some pictures so we can see what you're looking at.
 
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the upper is my old part. the whole sterndrive is the new one
 

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greno

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Nov 23, 2012
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Ok, yours is an early alpha one. The new one is an old Mercruiser #1 (MC-1) drive. They should interchange.
 

greno

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Did you remember to perform a gimbal alignment with the bar before you tried inserting the new drive? You may be off far enough that it won't go.
 
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i did not have the tool so i did not do that is that a must? also when i tried to put in the first time i pulled the bering out thats when i relized the shaft was the wrong size so exchange with the old one.
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
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19,447
both shafts are the same diameter , the MC1 may be shorter . What was the length of the damaged drive you removed
 

greno

Petty Officer 2nd Class
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Nov 23, 2012
Messages
182
i did not have the tool so i did not do that is that a must? also when i tried to put in the first time i pulled the bering out thats when i relized the shaft was the wrong size so exchange with the old one.

The shafts are the same. The new one probably had some corrosion on it or was buggered up in some way.
And yes, you need to do a gimbal alignment to be sure you have things lined up.
 
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