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WileyOne

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A few months ago, I changed the serpentine belt on my 2001 MerCruiser 5.0 260hp EFI. It is sitting on the trailer and the "ear muffs" are connected to a garden hose. This is the first time I've started the engine since that change.
It fired up nicely and I set the RPMs to 1100. Water is spraying all over the place, mostly because the rubber cups are not making a good seal against the sterndrive body.
The temperature gauge took 5-10 minutes to get up to 170F, then settled back and stabilized at about 165. I assume this is because the thermostat opened.
I am hearing a mid-pitched whining sound coming from the engine but I am unable to determine the exact source. It could be the water pump, alternator, belt tensioner, or something else.
The battery gauge stayed a little over 12V, maybe 12.7

My questions:
  • How do I know if I have the correct tension on my serpentine belt?
  • Could a belt that is too tight, or not tight enough, cause my whining sound?
  • How can I diagnose the source of the whining sound? Might it be normal?
  • Are my battery and temp readings fairly typical?
  • Are the earmuffs supposed to seal so that no water sprays out? Do I need to buy a new set?
  • If the earmuffs are sealed tightly against the sterndrive body, where is the water supposed to exit?

Thanks for any guidance you can offer.
It is beginning to get cold in Virginia. I need to get some pink stuff in there.

splash4M.jpg
 
It's generally speaking not a good idea to run the engine on the garden hose for any length of time. For one thing it may not be supplying sufficient water to the intake pump leading to overheat issues. Couple minutes, OK but anything more than that you should have it in the water.

There are two approaches to winterizing. One is to drain everything completely with the theory that no fluid in the engine allows no chance for freeze damage. The second is to fill the engine with antifreeze completely so that there is no clear water to freeze. Both have their advantages and disadvantages. Mercruiser does not take a stand one side or the other. Whichever way you go, be sure to do it by the book.

Can't address the whining but this is usually the alternator, power steering pump, circulating pump, tensioner pulley or seawater pump. If you only have 12.7 with the engine running I would suspect that the alternator is boo how.
 
most serpentine belts have a tensioner to eliminate the slack...and most of those have indicators to tell you when the belt has stretched too far to where it can't maintain tension...manuals are great for those details...
 
o2batsea said:
It's generally speaking not a good idea to run the engine on the garden hose for any length of time.
Click to expand...

What do you mean by "any length of time"? To get the thermostat to open, the engine must run until it comes up to temperature. I chose 1100 RPM because that seems to be a reasonable speed. The only way to get the engine up to temperature faster would be to run at a greater RPM, which I think would be a very bad idea. As I said, it took about 10 minutes to reach equilibrium at 165F. Are you saying that is a bad thing? The pink stuff isn't going to get into the engine block any other way except through the thermostat.

Once I decided that the thermostat had opened, I shut it down within 2 to 3 minutes. The temp never went about 170F, probably because the water from the hose is really cold. How could that possibly cause any problems?

When you say "by the book", what book are we talking about and where can I get one?

Your response to my post was interesting, and I thank you for it, but it mostly addressed questions that I did not ask and lacked any actionable information.

I have a new set of ear muffs coming from Amazon today. I will try this procedure again tomorrow. The priority is to get the pink stuff in there before a hard freeze occurs. I can worry about the whining in the spring.
 
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Re: amateur mechanic learning as I go

makomark said:
most serpentine belts have a tensioner to eliminate the slack...and most of those have indicators to tell you when the belt has stretched too far to where it can't maintain tension...manuals are great for those details...
Click to expand...

My engine does not have a belt tensioner, only an idler pulley. I do not see a way to measure it or adjust it.
To get the belt off and on, I had to loosen the alternator mount and rotate it slightly, like I used to do on my '71 Pontiac 400ci.
I might have over tightened or under tightened the belt.

How can I be sure?

I don't remember hearing that whine the last time I ran the engine with the cover off, so I feel like something has changed.


belt3M.jpg
 
WileyOne said:
What do you mean by "any length of time"? To get the thermostat to open, the engine must run until it comes up to temperature. I chose 1100 RPM because that seems to be a reasonable speed. The only way to get the engine up to temperature faster would be to run at a greater RPM, which I think would be a very bad idea. As I said, it took about 10 minutes to reach equilibrium at 165F. Are you saying that is a bad thing? The pink stuff isn't going to get into the engine block any other way except through the thermostat.

Once I decided that the thermostat had opened, I shut it down within 2 to 3 minutes. The temp never went about 170F, probably because the water from the hose is really cold. How could that possibly cause any problems?

When you say "by the book", what book are we talking about and where can I get one?

Your response to my post was interesting, and I thank you for it, but it mostly addressed questions that I did not ask and lacked any actionable information.

I have a new set of ear muffs coming from Amazon today. I will try this procedure again tomorrow. The priority is to get the pink stuff in there before a hard freeze occurs. I can worry about the whining in the spring.
Click to expand...
I mean ten minutes is OK if that's what it takes to open the Tstat but then do what you gotta do and shut it down. There are enough stories of folks blowing their otherwise good engines with this technique so you don't have to take my word for it.
If you believe in Antifreeze over plain old air, then follow the step by step instructions in the Mercruiser owners manual, which is readily available as a downloadable pdf on several sites. That book.
I don't tell people what to do. Nobody listens to me anyway so I don't bother anymore. It's up to you to research the information, and decide on your own what steps to take.
 
Re: amateur mechanic learning as I go

WileyOne said:
My engine does not have a belt tensioner, only an idler pulley. I do not see a way to measure it or adjust it.
To get the belt off and on, I had to loosen the alternator mount and rotate it slightly, like I used to do on my '71 Pontiac 400ci.
I might have over tightened or under tightened the belt.

How can I be sure?

I don't remember hearing that whine the last time I ran the engine with the cover off, so I feel like something has changed.


View attachment 28030
Click to expand...

the idler moves up and down almost like a rack and pinion. Hold the stud on it loosen the nut, then you should be able to turn the stud - one way will put more tension on the other less tension .

An on the earmuffs, yes water should blow by them if you have good water pressure. if you keep rpms down below 1500 and it didn't over heat you should be ok, just make sure water comes out the idle relief ports.

you may want to invest in a factory manual info like this is in there
 
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Re: amateur mechanic learning as I go

WileyOne said:
My engine does not have a belt tensioner, only an idler pulley. I do not see a way to measure it or adjust it.
To get the belt off and on, I had to loosen the alternator mount and rotate it slightly, like I used to do on my '71 Pontiac 400ci.
I might have over tightened or under tightened the belt.

How can I be sure?

I don't remember hearing that whine the last time I ran the engine with the cover off, so I feel like something has changed.


View attachment 28030
Click to expand...

the 'by the book' reference applies to me as well....Dieter described the actual adjustment process.

The factory manual say 1/4" deflection with moderate thumb pressure....the better answer (in the newer models' factory book) says to use a belt deflection gauge...
 
'88 FW instrument panel.jpgMerc Quicksilver muffs.jpg
1) you buy a belt tension gauge, OTC makes a very nice one, I've had one for years, this way you get it right and no guessing
2) temp is normal if you have a 160 thermostat, voltage is low check it the batteries and alternator, dash gauges sometimes read low, should be 14V with the engine running with good batteries, clean connections good alt and tight belt
3) if any of the bearings of the accessories or idler pulleys are wearing, that could be your whine, I use a mechanic's stethescope to find noises easily, if you remove the belt, each one should spin very smoothly you can often feel roughness that causes noise
4) the water should exit right under the transom mount if you are getting adequate water supply.
I've used various muffs over the years and the best ones I've used are the Merc/Quicksilver ones with the metal rod clamp, they fit better because the rubber is softer and with the clamp they cannot fall off. I used to use the Tempo dual inlet style but they changed the rubber and its too stiff to seal well.
 
louc said:
1) you buy a belt tension gauge, OTC makes a very nice one, I've had one for years, this way you get it right and no guessing
2) temp is normal if you have a 160 thermostat, voltage is low check it the batteries and alternator, dash gauges sometimes read low, should be 14V with the engine running with good batteries, clean connections good alt and tight belt
3) if any of the bearings of the accessories or idler pulleys are wearing, that could be your whine, I use a mechanic's stethoscope to find noises easily, if you remove the belt, each one should spin very smoothly you can often feel roughness that causes noise
4) the water should exit right under the transom mount if you are getting adequate water supply.
I've used various muffs over the years and the best ones I've used are the Merc/Quicksilver ones with the metal rod clamp, they fit better because the rubber is softer and with the clamp they cannot fall off. I used to use the Tempo dual inlet style but they changed the rubber and its too stiff to seal well.
Click to expand...

Thank you for addressing all the items on my list.
All went well with the winterizing. I bought a new set of muffs and it sucked in 2.5 gallons of pink stuff. Winters aren't real cold in Virginia. Should be fine.
Today I ordered the OTC belt tension gauge from Amazon for $22.
Now that the engine is winterized, I won't hear that noise again until April. Will pick up a stethoscope then.
If it needs an alternator, I'll be looking to beef it up a little.
 
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