Alpha one leg issues

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Jun 30, 2008
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:):)The first time I started the engine it makes a high pitch noise. Like a bad belt. I lubed all the pully bearings, sprayed belt dressing and made no difference. Even when I rev the engine the noise is constant. I was running the engine on land with ear muffs connected to a water hose. I took off a hose from the water pump and it had water in it. I had changed the hoses so I know that water is running through the block ok. is the water pump (impeller) or alternator bushings? The sound is loud but I think its comming from the carb? The engine is a 5.7 Mercruiser 1997 withe a carb. The engine sound great except for the High Pitch noise.:confused:
 
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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

Thanks. I'll get the tool and try it on Saturday June 5th.
 

Fishermark

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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

Take the belt off and see if the noise disappears. That will help narrow down and identify the source.
 
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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

I took the belt off and the damn noise is still there. I have no idea what it could be now. the carb of fuel filter/pump?
I will by the tool so maybe I can isolate the noise.
 
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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

I ran the engine with the arrestor on and off the carb but still the noise. Would it be safe to rune the engine for 10 min to see if it quitens down once warmed up? This is the first time I have cranked her up this year. I am going to change the fuel filter/water seperator.
At least I know its not the impellor, tensioner pully, stearing pump, or the alternator.
 

Bondo

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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

The sound is loud but I think its comming from the carb? The engine is a 5.7 Mercruiser 1997 withe a carb.

Ayuh,...... What Carb,..??..??

I think you've got a Vacuum Leak,....
Bad Gasket, or Hose maybe,....

At Idle,.....
Spray around the Carb, the base of the Carb,+ where the Intake bolts to the heads with WD-40,....
It should Rev Up if you find a Leak,...
 

Uraijit

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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

An unlit propane torch works for pinpointing vacuum leaks. It's also easier to control the flow of, etc.
 
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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

Thanks guys. I fixed it. a bolt holding the carb down was loose. Once I tightened it the noise stopped.
But I have another problem now. The boat is over Heating. The water is not getting suked in at the leg like it use too. Its prity much not pulling in any water. just a litlle. I took the water pump off and it was full ov water. so are the water hoses.
 

Bondo

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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

Ayuh,....

What Drive do you have,....
Has the raw water Impeller been changed,..??
 
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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

it's a alpha one and no the impeller has not been changed.
Where can I locate the impellor.
The water pump on the front of the engine block is fine.
 

Bondo

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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

Ayuh,...

The Important,+ prone to failure Waterpump is mounted in the Lower Unit of the Outdrive.....
It's Rubber Impeller should be changed every year or 2, or whenever there's an Overheat Issue....
 
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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

I purchased a impeller kit and will replace it tomorrow. I will also put the water pump back on engin. This is what owning a boat is about. Spend more time on it on land than on the water.
 

Fishermark

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Re: High Pitch noise like a Jet. 5.7 Mercruiser

Re: High Pitch noise like a Jet. 5.7 Mercruiser

Not being picky, but just for future reference to avoid anyone misunderstanding what you are saying / asking... the "water pump" is the one in the outdrive, while the one on the engine is referred to as the "circulating pump." Different from a car I know, but that helps keep everyone on the same page. ;)
 
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All fixed and ready to hit the water.

All fixed and ready to hit the water.

Thanks guys.
Yes I had made the mistake of thinking the Water Circulator as a Water Pump. I purchased the impeller kit and replaced it this morning. The boat is running great. Sucks up the water and is running very quiet.
Thanks again.
 
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Re: High Pitch noise like a Jet. 5.7 Mercruiser (ALL FIXED)

Re: High Pitch noise like a Jet. 5.7 Mercruiser (ALL FIXED)

So I ran the boat for about 15 min and noticed a bit of white grease build up inside the walls of the prop. I checked the oil in the block and the gear oil level. Its all fine. I did put grease on the end of the shaft as i replaced the lowere portion of the leg. Any ideas?
 
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Re: Alpha one leg issues

Ok so I ran the boat again and its fine. No oil/grease only clean water comming out of the leg.
 
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