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Old 03-26-2019, 08:03 PM   #21
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Originally Posted by Xsbank View Post
Why waste your time changing that filter. It’s still new. Filters are cheap but changing them too soon is just a pointless, messy waste of time. Just think of all the other fun stuff you could be doing?

Why waste the money/effort/etc if you have a vacuum gauge? What is the point of the gauge if you change filters annually? If the gauge doesn’t register any restriction, why do you change out a good filter?

“Weird strange customs that boatowners believe.”
You put an awful lot of faith in a cheap vacuum gauge.

The other part about changing them annually is that even though the engine hasn't quit, you can see how close you are to a plugged filter. Maybe you got a bad load of fuel and it's time to decide if you're going to be going through some filters before the crud is out of the tank.

Now I fully realize that you could pull the filter, check it, and put it back in. If I'm going to the trouble of pulling the filter, for $10 or less in bulk, I'm putting a new one in. When it comes to filters, I'm happy to spend money.

Ted
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Old 03-26-2019, 08:07 PM   #22
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Originally Posted by Seevee View Post
Thought you had a single... or are you referring to the genny, too?
Only have one propulsion engine in this boat. The plural was more of a generality for others.

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Old 03-28-2019, 08:38 AM   #23
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Vacuum gauge is useless under no-load conditions

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Originally Posted by Delfin View Post
Well, no. While it is true that with a clean filter the vacuum only goes up when you suck a lot of fuel, it also goes up when the filter is clogged. That's the whole point of those gauges.
Well, yes. Whether the OP's filter is clean or dirty, that vacuum gauge is useless when the engine is under no-load.

Think it through. A Racor 1000 is a 180gph filter. At idle or no-load off idle, the engine in question will be drawing less than 1gph (about 0.5% of the Racor's flow capacity).

I said that any time this engine is running under no-load, the vacuum gauge will be useless. This is because, under no-load, if the vacuum gauge starts increasing, it means you should have changed the filter a loooonnnngggg time ago.

I know this seems counter-intuitive. Maybe it will help if I say it differently.

If you begin showing increasing vacuum on a 180gph filter, when you are only pulling 0.8gph through the filter, it means the filter is TOTALLY plugged. It means the filter was WAY overdue for changing.

That is why the vacuum gauge is useless when there is no load on the engine. If you wait until you see vacuum increasing at no-load, it is long past time that you should have changed the filter.

If you read the thread from the beginning, you will see this is exactly what happened here.

The whole gist of OP's question is:

Q. "why didn't my vacuum gauge tell me that my filter was totally plugged?"

A. Because your vacuum gauge readings were taken when the engine was not sufficiently loaded, and under these conditions, your vacuum gauge is useless.

Yes, I am belaboring the point, because this is yet another very common misconception that causes significant safety concerns. It is a misconception that is common even among very experienced boaters!

Why is it a safety concern? If one is only looking at their filter's vacuum gauge when the engine is under no load, they will have no idea when the filter becomes significantly plugged. They will then be surprised when they need power from the engine (outrunning a storm or navigating a tricky pass) and it's not there.
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Old 03-28-2019, 09:33 AM   #24
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Originally Posted by Riverguy View Post
Well, yes. Whether the OP's filter is clean or dirty, that vacuum gauge is useless when the engine is under no-load.

Think it through. A Racor 1000 is a 180gph filter. At idle or no-load off idle, the engine in question will be drawing less than 1gph (about 0.5% of the Racor's flow capacity).

I said that any time this engine is running under no-load, the vacuum gauge will be useless. This is because, under no-load, if the vacuum gauge starts increasing, it means you should have changed the filter a loooonnnngggg time ago.

I know this seems counter-intuitive. Maybe it will help if I say it differently.

If you begin showing increasing vacuum on a 180gph filter, when you are only pulling 0.8gph through the filter, it means the filter is TOTALLY plugged. It means the filter was WAY overdue for changing.

That is why the vacuum gauge is useless when there is no load on the engine. If you wait until you see vacuum increasing at no-load, it is long past time that you should have changed the filter.

If you read the thread from the beginning, you will see this is exactly what happened here.

The whole gist of OP's question is:

Q. "why didn't my vacuum gauge tell me that my filter was totally plugged?"

A. Because your vacuum gauge readings were taken when the engine was not sufficiently loaded, and under these conditions, your vacuum gauge is useless.

Yes, I am belaboring the point, because this is yet another very common misconception that causes significant safety concerns. It is a misconception that is common even among very experienced boaters!

Why is it a safety concern? If one is only looking at their filter's vacuum gauge when the engine is under no load, they will have no idea when the filter becomes significantly plugged. They will then be surprised when they need power from the engine (outrunning a storm or navigating a tricky pass) and it's not there.
You appear to be the only one who thinks the OP's reading of the vacuum gauge took place under no load. He doesn't appear to say that, but perhaps I missed it. The gauges work just fine when used as directed, like most equipment in widespread use does.

From Racor:

Monitoring the black needle to ensure it does not reach this setting has been difficult as the operator must observe the needle while the engine is running at service speed (the gauge is not always mounted in a location that is easy to monitor).
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Old 03-28-2019, 09:34 AM   #25
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Quote:
Originally Posted by Riverguy View Post
The whole gist of OP's question is:

Q. "why didn't my vacuum gauge tell me that my filter was totally plugged?"

A. Because your vacuum gauge readings were taken when the engine was not sufficiently loaded, and under these conditions, your vacuum gauge is useless.
Sorry, I don't really want to get involved in this because you both seem to know what you are talking about, but approaching it with different semantics. However, the OP did mention he had a "telltale" I assume that is the sweep gauge that records the highest reading encountered. So as long as he ran the engine up, it doesn't matter what the RPM's were at the time he looked at the gauge.
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Old 03-28-2019, 09:52 AM   #26
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Sorry, However, the OP did mention he had a "telltale" I assume that is the sweep gauge that records the highest reading encountered. So as long as he ran the engine up, it doesn't matter what the RPM's were at the time he looked at the gauge.
That's a good point assuming he ran the engines up under load. This is an interesting thread for me as I have Duel Racor 1000s & have yet to see any significant rise of the "telltale." Not many hours of running since the Duel Racor installation, however. (Health issues.)
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Old 03-28-2019, 09:56 AM   #27
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Yes Codger2, I have never seen my needle move much, either. I'm in the camp that changes annually anyway because I believe the membrane of the filter deteriorates over time so it wears out whether used or not.

I admit that I don't know that applies to RACOR filters for a fact. But I do know Yanmar states it is true for their secondary filters.
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Old 03-28-2019, 10:00 AM   #28
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Sorry, I don't really want to get involved in this because you both seem to know what you are talking about, but approaching it with different semantics. However, the OP did mention he had a "telltale" I assume that is the sweep gauge that records the highest reading encountered. So as long as he ran the engine up, it doesn't matter what the RPM's were at the time he looked at the gauge.
That would be the "new and improved" gauge Racor came out with that includes a trailing needle showing max pressure. They say they added this since when the engine is running at load the needles can be bouncing around, or the gauge may be mounted in an inconvenient place to read when the engine is running at normal loading. In any case the gauges work, and the lesson here, I think, is that these filters can get pretty nasty looking and still be doing their job.
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Old 03-28-2019, 10:21 AM   #29
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FWIW, Bob Senter from Lugger/Northern Lights, states that filters should be changed at a minimum of every year because they do deteriorate, even when not being used, that includes both primary and secondary.
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Old 03-28-2019, 10:47 AM   #30
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Second that about the filters aging. Seen a few over a few years old where the grommet around center post was loose, plastic must have degraded. This allows fuel (and crud) to bypass.

I change mine at least once a year (900 Racor single) and before a long trip. Mine looks like the OP, black gunk, probably asphaltenes on it , but no slime. I can look at the bottom of my tanks and they are shiny aluminum, no visible crud. I think the asphaltenes precipitate out with time.

I am fortunate that my engine has a lot of return flow so fuel gets polished just by running. Engines with little return flow don't get this advantage.

I don't use a vacuum gauge. I think most are cheaply made and seen several that did not work. Either gauge in hand showed high vac (impossible) or close off supply valve and gauge did not rise even though suction flow blocked (note this trick does not work on dual racors with single selector valve). Also found one gauge that leaked under suction and caused an engine stall and related "cap'n crunch".

I can tell if my filter is getting cloggy as when I power up with dirty filter, engine rpms take a bit to build, then comes up. New filter and all is good.
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Old 03-28-2019, 11:31 AM   #31
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Originally Posted by O C Diver View Post
You put an awful lot of faith in a cheap vacuum gauge.

The other part about changing them annually is that even though the engine hasn't quit, you can see how close you are to a plugged filter. Maybe you got a bad load of fuel and it's time to decide if you're going to be going through some filters before the crud is out of the tank.

Now I fully realize that you could pull the filter, check it, and put it back in. If I'm going to the trouble of pulling the filter, for $10 or less in bulk, I'm putting a new one in. When it comes to filters, I'm happy to spend money.

Ted
"You put an awful lot of faith in a cheap vacuum gauge"
FWIW - the vacuum gages in our past 3 boat have been very accurate for diagnostics and well as filter changes.
On one occasion with a new filter installed the gage 'told' us that ridiculous check ball was stuck in the filter track.
In another case just after a new filter was installed we saw high pressure and tracked down a pinched fuel line.
They work and are very valuable for not much expense....
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Old 03-28-2019, 05:37 PM   #32
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Thanks Delfin...

Quote:
Originally Posted by Delfin View Post
You appear to be the only one who thinks the OP's reading of the vacuum gauge took place under no load. He doesn't appear to say that, but perhaps I missed it. The gauges work just fine when used as directed, like most equipment in widespread use does.

From Racor:

Monitoring the black needle to ensure it does not reach this setting has been difficult as the operator must observe the needle while the engine is running at service speed (the gauge is not always mounted in a location that is easy to monitor).

Thank you for confirming that Racor confirms that the vacuum gauge is useless when the engine is running under no load.


Still, Racor's dumb language adds to the confusion.


When I say "the vacuum gauge is useless when the engine is running under no load" and Racor says "...the operator must observe the needle while the engine is running at service speed", how are those different?


Here's how they are different.


For someone who normally runs at 1,800 rpm, they >>might<< think that running at 1,800rpm in neutral this is the same as "running at service speed". This is not true. When the engine is running at 1,800 rpm under no load, it is barely drawing more fuel than it would running at idle under no load.


This is a common misconception I have wittnessed dozens of times here on trawlerforum and pretty much everywhere else I go. Folks just can't seem to grasp the idea that engines draw fuel in proportion to the load presented -- not the rpm spinning. The load on a diesel engine determines how many GPH it is pulling, not the RPM!

Re: "You appear to be the only one who thinks the OP's reading of the vacuum gauge took place under no load."


All I had to do was look at his filter photos to know. That, and seeing dozens of people make the same mistake over the last 30 years or so (including me, once upon a time).
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Old 03-28-2019, 05:47 PM   #33
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Originally Posted by Riverguy View Post
Thank you for confirming that Racor confirms that the vacuum gauge is useless when the engine is running under no load.


Still, Racor's dumb language adds to the confusion.


When I say "the vacuum gauge is useless when the engine is running under no load" and Racor says "...the operator must observe the needle while the engine is running at service speed", how are those different?


Here's how they are different.


For someone who normally runs at 1,800 rpm, they >>might<< think that running at 1,800rpm in neutral this is the same as "running at service speed". This is not true. When the engine is running at 1,800 rpm under no load, it is barely drawing more fuel than it would running at idle under no load.


This is a common misconception I have wittnessed dozens of times here on trawlerforum and pretty much everywhere else I go. Folks just can't seem to grasp the idea that engines draw fuel in proportion to the load presented -- not the rpm spinning. The load on a diesel engine determines how many GPH it is pulling, not the RPM!

Re: "You appear to be the only one who thinks the OP's reading of the vacuum gauge took place under no load."


All I had to do was look at his filter photos to know. That, and seeing dozens of people make the same mistake over the last 30 years or so (including me, once upon a time).
That's impressive. Although the OP never says he reads his gauge under no load (who does, anyway?), you can divine he is and when telepathy fails, you can also do so just by looking at a dirty filter. Wow.
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Old 03-28-2019, 06:14 PM   #34
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Quote:
Originally Posted by smitty477 View Post
"You put an awful lot of faith in a cheap vacuum gauge"
FWIW - the vacuum gages in our past 3 boat have been very accurate for diagnostics and well as filter changes.
On one occasion with a new filter installed the gage 'told' us that ridiculous check ball was stuck in the filter track.
In another case just after a new filter was installed we saw high pressure and tracked down a pinched fuel line.
They work and are very valuable for not much expense....
To be clear, I have them and watch them, but it's still a pretty low quality gauge. Have seen more than one fail to read at all with a plugged filter. See Ski's comments below.

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Originally Posted by Ski in NC View Post
I think most are cheaply made and seen several that did not work. Either gauge in hand showed high vac (impossible) or close off supply valve and gauge did not rise even though suction flow blocked (note this trick does not work on dual racors with single selector valve). Also found one gauge that leaked under suction and caused an engine stall and related "cap'n crunch".
Ted
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Old 03-28-2019, 08:48 PM   #35
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Originally Posted by Riverguy View Post
Well, yes. Whether the OP's filter is clean or dirty, that vacuum gauge is useless when the engine is under no-load.

Think it through. A Racor 1000 is a 180gph filter. At idle or no-load off idle, the engine in question will be drawing less than 1gph (about 0.5% of the Racor's flow capacity).

I said that any time this engine is running under no-load, the vacuum gauge will be useless. This is because, under no-load, if the vacuum gauge starts increasing, it means you should have changed the filter a loooonnnngggg time ago.

I know this seems counter-intuitive. Maybe it will help if I say it differently.

If you begin showing increasing vacuum on a 180gph filter, when you are only pulling 0.8gph through the filter, it means the filter is TOTALLY plugged. It means the filter was WAY overdue for changing.

That is why the vacuum gauge is useless when there is no load on the engine. If you wait until you see vacuum increasing at no-load, it is long past time that you should have changed the filter.

If you read the thread from the beginning, you will see this is exactly what happened here.

The whole gist of OP's question is:

Q. "why didn't my vacuum gauge tell me that my filter was totally plugged?"

A. Because your vacuum gauge readings were taken when the engine was not sufficiently loaded, and under these conditions, your vacuum gauge is useless.

Yes, I am belaboring the point, because this is yet another very common misconception that causes significant safety concerns. It is a misconception that is common even among very experienced boaters!

Why is it a safety concern? If one is only looking at their filter's vacuum gauge when the engine is under no load, they will have no idea when the filter becomes significantly plugged. They will then be surprised when they need power from the engine (outrunning a storm or navigating a tricky pass) and it's not there.
I do something I am certain is very uncommon but simple and foolproof. My boat has Davco filter housings. These are very common to the trucking industry. The time to change the filter is when the fuel reaches the top of the clear housing. No need for a vacuum gauge. No need for guessing. No need for prematurely changing out a perfectly good filter. Bonus - changing filters is a simple, no-mess task.
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Old 03-28-2019, 08:52 PM   #36
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I do something I am certain is very uncommon but simple and foolproof. My boat has Davco filter housings. These are very common to the trucking industry. The time to change the filter is when the fuel reaches the top of the clear housing. No need for a vacuum gauge. No need for guessing. No need for prematurely changing out a perfectly good filter. Bonus - changing filters is a simple, no-mess task.
Those are very cool.
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Old 03-28-2019, 09:04 PM   #37
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IF in doubt, change the filter. You dont want the engine to stall at a 'most inconvenient' time such as riding a wave through a cut. You might turn side ways if the engine stalls and sideways is not a good thing.

Filters are cheap insurance.

AND, when was the last time you had your vacuum gauge calibrated?
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Old 03-28-2019, 09:06 PM   #38
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2) I think you are probably wasting time and effort by running new fuel through the 2 micron 'polishing' before adding to your tanks. Most of what you are seeing is microbial biofouling, and this is growing inside your tanks, not as a result of contaminated fuel. This is a common problem that is particularly prevalent in high-humidity climates and where tanks are not normally kept full. Humidity in the air condenses on the inside surfaces of the tanks and the condensate water feeds the growth of the microbes. There is a good white paper on this at http://www.hpcdfuel.com/pdf/DOWfuel_training.pdf
This is often proposed in theory and seldom tested. But Maine Sail (CMS) has tested it. It does not happen, at least in his tests.
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Old 03-29-2019, 05:45 AM   #39
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IF you are blessed with a polishing system, you can put the polisher on and let it run to your hearts content. SMILE
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Old 03-29-2019, 07:11 AM   #40
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"(the gauge is not always mounted in a location that is easy to monitor)."

If the gauge is located in the Hell Hole on top of the filter , it might be dangerous to change out the plugged filter with the engine operating.

At best it will be loud and over 100F , moving the filter bank to a location out of the HH only requires some hose.
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