How does the mercruiser stern drive engage when you move it forward and reverse?

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toolman4

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The grinding noise it makes when you first engage it in forward or reverse, what is actually going on that makes that noise? Some is normal right? This is on a mercruiser alha one gen 2 hooked to a 4.3 merc carbed. What rpm should the idle be set at ? Mines around 600rpm.
 
Bt Doctur

Bt Doctur

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Re: How does the mercruiser stern drive engage when you move it forward and reverse?

Assuming you asking about the Alpha drive,the way the gears are cut they make that noise going into gear.you should be shifting firmly.
around 750 in gear, in the water, in forward gear
 
Don S

Don S

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Re: How does the mercruiser stern drive engage when you move it forward and reverse?

Shift it briskly, don't try to go slow and be easy on it. That does more harm than good. At normal idle, it should go into gear with a single clunk.
 
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toolman4

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Re: How does the mercruiser stern drive engage when you move it forward and reverse?

What about the shift cutout switch? Is it supposed to stop a clutch on the output shaft while shifting briskly so the gears mesh before the clutch engages again.
 
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toolman4

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Re: How does the mercruiser stern drive engage when you move it forward and reverse?

Thanks for all info. Now I get. I was checking to make sure things were operating right on the drive before I take it to the lake. I understand now that it isn't going to shift and cutout correctly on the muffs. All my prechecks are done and now I can give it the real test! What do you reccomend for the new long block break in? Run it like I stole it :D to seat the rings or take it easy for so many hours?
 
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haulnazz15

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Re: How does the mercruiser stern drive engage when you move it forward and reverse?

Keep it under 3K rpms for the first few hours and vary the rpms so that you don't spend too much time at one speed. Once you get a few hours or so on it, then push it further up the rpm band. After 5 hours or so, the rings are set for sure so run it like ya stole it if you like. As with most things, there are varying opinions on break-in procedures, but this is mine.
 
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toolman4

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128
Re: How does the mercruiser stern drive engage when you move it forward and reverse?

Sounds good. I hear ya about the varying opinions. I've had good luck breaking in snowmobiles warming them up real good and then running them hard to seat the rings real good. Never tried on bigger motors however. I'll start slow with the varying throttle technique. Thanks for the reply.
 
jimmbo

jimmbo

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May 24, 2004
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12,964
Re: How does the mercruiser stern drive engage when you move it forward and reverse?

Someone here must have a MerCruiser Manual and could quote what it says about break in.

About the "Run it like you stole it" statement. Would it mean... Drive the snot out of it? Or... Drive it very nicely, doing nothing to attract the attention of the local Gestapo?
 
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