New here, have some Mercruiser 5.7 questions

Igearhed

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Jun 1, 2008
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Hello, my first post here so I'll introduce myself. I am an auto tech in Richmond VA. My shop specialises in Euro cars, but my expertise is with Honda products. So if anyone has any car questions, especially BMW, or Honda related then shoot em my way. I'll be happy to help if I can. I have never worked on marine apps before, so I'm not sure about the big differences if any.

Ok, on to my questions. I'm working with a 5.7 Mercruiser Alpha 1. I'm not sure if its a 1980 or 1994 model engine. The story is the boat is a 80, but the engine was "re-powered" in 94. Not sure if the guy means rebuilt or replaced. I'm hoping y'all can help me out with that, the serial # is: 0F120436. The drive # is: 0F100097 and the transom # is: 0F189990. All of this was relayed to me over the phone and having never worked with boats before I'm not sure witch one or if any/all of these numbers I need. I'm gonna give this a shot for my father-in-law.

I have not gotten my hands on the boat yet so see if I can even duplicate this problem at all, or if I'll be able to do it with out putting it in the water. According to the guy he picked this thing up from, the boat will run strong and hard for as long as you like. If you cut it off it will not restart until it cools down. Sounds to me like a vapor lock issue, and I've done a bit of research in the forums here that tell me I'm on the right track with that. Is there something I could be overlooking? Are there ignitors, condensers, and/or coils that tend to overheat on these things?

The guy says that he and his mechanic have replaced "just about everything" and they seem to think its a wire harness problem. Not having had a chance to see this happen for myself I disagree with that. If there were some high heat caused resistance in a sensor or wires in the harness I would think that the problem would happen as soon as it got hot, not only after it has been shut down. Is that wrong because were talking about a marine engine here?

Last thing... What are some common problems and areas of concern I need to keep an eye out for with this engine? Standard troubleshooting issues like no spark, fluid leaks, compression, head and block problems I'm sure are the same as any other internal combustion engine. So what are some marine engine specific problems I may run across on this application? Let me say now, that I know absolutely nothing about the drive or prop. That includes correct terminology...

Thanks in advance for any help. I'm sure I'll be lingering around here on a regular basis as problems arise.
 

Fishermark

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Oct 19, 2003
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5,617
Re: New here, have some Mercruiser 5.7 questions

First... welcome. :)

Second, there are many things that are unique to a boat engine, but you're right - many of the same troubleshooting techniques will apply.

One thing you need to be aware of is to always make sure you have water supplied to the engine whenever you try and start it. You can use a set of "muffs" to supply water to the outdrive and hence the engine. Many think to themselves, "Well, I will just run it for a short time without water just to make sure it runs...." Don't do it! It will burn up the impeller in short time.
 

Don S

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Re: New here, have some Mercruiser 5.7 questions

Those are the numbers you need, and it could be a 93 or 94 (I can't tell exactly), but it's NOT a 1980.
The drive is an Alpha I Gen II and so is the transom shield.
Looks like the complete engine and drive package was replaced during the repower.

Without having the boat, I don't know how you are going to do any testing. If it won't start hot, the first thing you have to find out is what is missing. Fuel or ignition. Till then it's just a bunch of guessing which way to go.

Here are links to free OEM manuals for both your outdrive and engine.

http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/17/17cov2r2.pdf

http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/14/14cover.pdf
 

Igearhed

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Jun 1, 2008
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Re: New here, have some Mercruiser 5.7 questions

Thanks for the advice, and thanks for the links, those will help a ton. Also I'm obviously not planning on testing anything with out the boat here. Its supposed to be getting dropped off early this week. I'm just trying to see if there is some common issue or some marine engine specific issue to look into first. We all know it cant be fixed if its not broke so first things first I need to duplicate the problem. I'm just fishing for a "I see that all the time, _______ is usually the cause, and _____ usually fixes it."

Thanks for clearing up the modle year for me too!
 
Last edited:

Bondo

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Apr 17, 2002
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71,084
Re: New here, have some Mercruiser 5.7 questions

I'm just fishing for a "I see that all the time, _______ is usually the cause, and _____ usually fixes it."

Ayuh,.... That Ain't gonna happen.....

That's a Proven motor that's been around, Probably longer than You have been......
 

Igearhed

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Joined
Jun 1, 2008
Messages
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Re: New here, have some Mercruiser 5.7 questions

Ayuh,.... That Ain't gonna happen.....

That's a Proven motor that's been around, Probably longer than You have been......

Yeah....figured it was worth a shot...
 

Bondo

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Apr 17, 2002
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71,084
Re: New here, have some Mercruiser 5.7 questions

Yeah....figured it was worth a shot...

Ayuh,...... Welcome Aboard to the forums here at iboats, anyways....

I see Don has already hooked you up with the Factory Manuals,....
That in itself will make you an Expert by the time you've read them all.....;)

Good Luck......
 
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